Jehovah's Witnesses strongly believe they are Christians, but their Jesus is different.  In the JW faith, Jesus is NOT God. Jehovah is God. However Witnesses believe they are saved through the ransom sacrifice of Jesus.
Christians are either saved or they're not saved. Either they follow Jesus or they don't. It's simple and it's what the Bible says. Christians don't work for salvation. They are saved by God's grace. They are not saved by their own righteousness or by following rules. They don't need to earn eternal life either. It's a free gift. All Christians are going to heaven. They know it for sure. There's no doubt in their mind that Jesus, God, and the Holy Spirit loves them. They put their complete trust in God and God saves his people. 
The Witnesses on the other hand, are never assured of salvation. They need to work hard for the 'prize' of eternal life. Not only must they be faithful to Jesus and follow him, they must also follow all the rules of the ancient God Jehovah, and be obedient to Watchtower leaders who believe they are God's channel of communication. 
Even if they work hard all their life, there's always doubt. Did I do enough for Jehovah?  One never knows.
The beliefs of the Witnesses are difficult for Christians and other religions to understand. We will simplify what they believe, so you can quickly grasp their perspectives in a few minutes.
Only 144,000 go to heaven to rule with Christ for a thousand years after armageddon. These are faithful men from the time of Jesus until today and includes Jehovah's Witnesses who have been chosen or 'anointed' by God to go to heaven. The ones living today out of the 144,000 are called 'the anointed remnant'. The anointed remnant today are not guaranteed eternal life. Even though they are anointed by God, congregation Elders and the Governing Body of Jehovah's Witnesses can disfellowship anointed ones. It is believed if someone is disfellowshipped they lose their place in heaven and someone will be selected by God to take their place. Watch this video about an anointed Witness who got disfellowshipped when she noticed a mistake in the organization's doctrines. 
The majority of Jehovah's Witnesses today believe they are part of 'the Great Crowd', who will live forever on a paradise earth after armageddon.  These ones are not guaranteed salvation either. They must be obey God, follow all of God's rules as explained by the Watchtower, and obey to congregation Elders until armageddon.
The Watchtower explains it the best. They say, ' In God’s new world, there will be “great ecstasy” when billions are resurrected, for “there is going to be a resurrection of both the righteous and the unrighteous.” (Acts 24:15; John 5:28, 29) These will be given a fresh start in life with the prospect of living from that time forward, even forever. The resurrected ones are not doomed to failure. Those who come back in the resurrection will not be condemned for sins they committed before they died. (Rom. 6:7) During Christ’s Millennial Reign, as the benefits of the ransom sacrifice are applied, obedient subjects of the Kingdom will grow to perfection, eventually becoming completely free from all the effects of Adam’s sin. (Rom. 8:21) Jehovah “will actually swallow up death forever, and the Sovereign Lord Jehovah will certainly wipe the tears from all faces.” (Isa. 25:8) God’s Word also says that “scrolls [will be] opened,” indicating that those living at that time will be given new information. (Rev. 20:12) As the earth is transformed into a paradise, “righteousness is what the inhabitants of the productive land will certainly learn.”—Isa. 26:9. The resurrected ones will be judged, not on the basis of sin inherited from Adam, but by what they themselves choose to do. Revelation 20:12 says: “The dead were judged out of those things written in the scrolls according to their deeds,” that is, their deeds following their resurrection. What a marvelous example of Jehovah’s justice, mercy, and love! Additionally, the painful things of their past life in this old world “will not be called to mind, neither will they come up into the heart.” (Isa. 65:17) With upbuilding new information available and a life filled with good things, they will no longer be distressed by the bad things of the past. Those past experiences can be put out of their minds. (Rev. 21:4) The same will be true of the “great crowd,” who survive Armageddon.—Rev. 7:9, 10, 14. In God’s new world, people will be able to live without getting sick again or dying. ' Watchtower Mar 15, 2009, Article: 'Keep Your Eyes on the Prize', Subtitle: 'Living Forever on Earth', par 7-10
JW's believe they are living in the time of the end. Soon Jehovah will destroy all the wicked ones at armageddon and establish his unified paradise world on earth. The implications of the resurrection for Jehovah's Witnesses is this.
If a JW (or someone from any faith) dies before armageddon, it doesn't matter what sins they've committed. They are guaranteed a resurrection to a paradise earth. According to the Watchtower quote (above), everyone will be given an opportunity to 'grow to perfection' and earn eternal life if they are obedient for a 1000 years.
If a JW makes it to armageddon, then Jehovah will judge if they are worthy or not. Did they keep all of Jehovah's rules as explained by the Watchtower? Did they do enough for Jehovah? Did they prove they are worthy? No one knows. Only Jehovah. That's why the salvation of JW's is uncertain. The organization implies that only JW's have any scriptural hope of surviving armageddon,  but that's not a guarantee that all JW's will survive. Some may not have done enough for Jehovah or angered him in some way. Perhaps they secretly broke rules, or in some other way are judged unworthy of eternal life. If a JW dies at armageddon, they believe they will never live again. They will perish forever with no hope of resurrection. 
In the JW faith, there are only two organizations, God's organization, - the Jehovah's Witnesses and Satan's organization, - everyone else. That's been a key doctrine since 1925. The implication of this is that God's organization will survive armageddon and Satan's organization will be destroyed. 
As we mentioned earlier, Jw's believe that if someone dies before armageddon, regardless of religion or lack of religion, they will be resurrected to life on earth. Billions will be saved but they won't be going to heaven, like they expect. Witnesses believe that when someone dies, they're dead. They're conscious of nothing at all. They do not exist until they're resurrected to life on a paradise earth (and given new body of course).
Even though they say 'billions' will be resurrected to life on a paradise earth, the Watchtower says this, 'Does this mean that every human who ever lived will be resurrected? No. ... Although Jesus will have a role in judging the living and the dead, Jehovah is the final Judge. (Acts 10:42) He will never resurrect those whom he judges to be wicked and unwilling to change.' WT, Book: 'What Does The Bible Really Teach?', p73, par 20
Jehovah's Witnesses believe they must fully support, cooperate, and obey God's organization (the Watchtower Society / publishing company) for salvation at armageddon. 
Everyone who calls upon the name of 'Jehovah' will be saved:
' But there are new heavens and a new earth that we are awaiting according to his promise, and in these righteousness is to dwell.”—2 Peter 3:12, 13. Peter was not here speaking of a destruction of the literal heavens and earth. The “heavens” and “earth” to which Peter referred in this context are symbolic of present corrupt human governments and of ungodly human society. “The day of Jehovah” will not destroy earth itself but will “annihilate the land’s sinners out of it.” (Isaiah 13:9) ... How, then, can anyone be saved in “the great and fear-inspiring day of Jehovah”? “The word of Jehovah” revealed to one of his prophets provides the answer to that question: “It must occur that everyone who calls on the name of Jehovah will get away safe.” (Joel 1:1; 2:31, 32) ' WT, Mar 1, 2002, Article: 'How Can You Survive the End of This World?'
NOTE: Even though JW's call upon the name of Jehovah, in the above quote, the Watchtower says the day of Jehovah will 'annihilate the land's sinners'. Does this mean JW's never sin? And if they do, what hope does the Watchtower give to it's members? Does Jehovah expect JW's to be free from sin in order to survive Armageddon? Is it possible for imperfect humans not to sin? If some sins are allowed, how many and which ones? JW's might be able to hide their sins from the Watchtower, but they can't hide from God.
Christians on the other hand are assured of salvation through Jesus Christ. It's a free gift that they 'inherit' by accepting Christ as their savior. JW's need to earn salvation. However slaving for Jehovah is not a guarantee of salvation. No matter how hard they work, in the end it may not be enough.
JW's are gathering up those who will be saved:
' It can confidently be said that the new world society of Jehovah’s Witnesses is the true, light-bearing organization today. ... And each year now, we see a continuing huge ingathering of people who also want to be spiritually enlightened. Hundreds of thousands are being baptized after studying the Bible and coming to an accurate knowledge of the truth. Truly, God’s “will is that all sorts of men should be saved and come to an accurate knowledge of truth.”—1 Timothy 2:4. ' WT, April 1, 1993, Article: 'Who Are Following the Light of the World?', Subtitle: 'Gathering the Light Bearers', Par 12
Breaking Jehovah's laws dishonors God's name:
' In fact, only Jehovah’s Witnesses today follow the example of Jesus’ early disciples and help people worldwide to ‘call on the name of Jehovah and be saved.’ They alone can truly be called “a people for his name.” (Acts 15:14) Is it possible, though, that we, too, may brush aside Jehovah’s name? Well, if we break Jehovah’s laws and practice unrighteousness, we are in fact dishonoring his name. ' Watchtower Jan 15, 1985, Article: 'How Do You View Jehovah's Name?', Subtitle: 'Keep Honoring the Name', Par 1,2
Jehovah will cleanse the earth:
' Today, something far more momentous than a natural disaster is coming upon mankind. It is the foretold act of Almighty God that will rid the earth of crime, wickedness, and associated problems. (Revelation 16:16; 21:3, 4) This momentous event is not a remote possibility but a certainty! Jehovah’s Witnesses are eager to share the knowledge needed to survive this impending world-shaking event with as many people as possible. ' Watchtower Sept 1, 2002, Article: 'Good Neighbors Are An Asset', Subtitle: 'The Greatest Neighborly Deed'
False religions and Christendom will be destroyed at armageddon:
' ... the antitypical ‘great tribulation’ did not begin in 1914 C.E. Rather, what took place upon Jerusalem’s modern antitype in 1914-1918 was merely ‘a beginning of pangs of distress’ . . . The ‘great tribulation’ such as will not occur again is yet ahead, for it means the destruction of the world empire of false religion (including Christendom) followed by the ‘war of the great day of God the Almighty’ at Armageddon.” ' Watchtower May 1, 1999, Article: “Let the Reader Use Discernment”, Subtitle: A Modern-Day “Disgusting Thing”, par 12
JW's expose false religions and the 'man of lawlessness', i.e. the clergy of Christendom:
Par 1: ' “Get out of her, my people, if you do not want to share with her in her sins, and . . . receive part of her plagues.”—REVELATION 18:4. ' Par 3: ' The time for God to execute his judgment against the man of lawlessness is fast approaching. Soon, as Jesus foretold, “there will be great tribulation such as has not occurred since the world’s beginning until now, no, nor will occur again.” (Matthew 24:21) That unprecedented time of trouble will begin with the execution of Babylon the Great, the world empire of false religion, which includes the religions of Christendom. The political elements “will make her devastated and naked, and will eat up her fleshy parts and will completely burn her with fire.” (Revelation 17:16) The great tribulation will end with the destruction of the remainder of Satan’s world at Armageddon, “the war of the great day of God the Almighty.”—Revelation 16:14, 16; 19:11-21. ' Par 14: ' Thus, Jehovah’s Witnesses must make known this inspired message regarding false religion: “Get out of her, my people, if you do not want to share with her in her sins, and if you do not want to receive part of her plagues. For her sins have massed together clear up to heaven, and God has called her acts of injustice to mind. . . . In one day her plagues will come, death and mourning and famine, and she will be completely burned with fire, because Jehovah God, who judged her, is strong.”—Revelation 18:4-8. ' Par 18: ' The clergy are part of Satan’s world. (John 8:44) But it is a world that God will soon crush out of existence. (2 Peter 3:11-13; 1 John 2:15-17) So God’s Word warns: “Whoever, therefore, wants to be a friend of the world is constituting himself an enemy of God.” (James 4:4) The clergy ignore that warning and continue to meddle in political affairs. They tell their followers that a better world will come through efforts of politicians. But that is a false hope, since this world under Satan is on its way out. ' Par 21: ' Therefore, God’s people will not hesitate to declare his vengeance against all of Satan’s world, including its man of lawlessness, the clergy of Christendom. ' Watchtower Feb 1, 1990, Article: ' Exposing “the Man of Lawlessness” '
1. Jesus is not God in the JW faith. He is God's son and lesser than Jehovah God his Father. See Do Jehovah's Witnesses Believe In Jesus Christ?
3. JW's must be obedient to the Governing Body and congregation Elders who enforce the rules of the organization. (i.e. 'God's Slave' and channel of communication) The Watchtower says this, 'And should we not strive to be obedient and submissive to those taking the lead in our local congregation?' WT, Nov 15, 2009, Article: 'Treasure Your Place in the Congregation', par 5.
4. Jehovah is the God of the ancient Israelites. He is a God of love, righteousness, judgment, and wrath upon those who disobey. Since Jehovah demands so much from His people, Witnesses sometimes wonder if they've done enough for Jehovah in order to be worthy of eternal life.
5. Learn everything JW's believe about the the 144,000
6. The Watchtower's promise of eternal life on a paradise earth filled with perfect people who never die is the illusive carrot that keeps Witnesses motivated to work hard for 'God's organization', the Watchtower, until 'the end' i.e. armageddon or the end of their life, which ever comes first. Learn what they believe about eternal life on a paradise earth
7. The Watchtower says, "Only Jehovah's Witnesses, those of the anointed remnant and the "great crowd," as a united organization under the protection of the Supreme Organizer, have any Scriptural hope of surviving the impending end of this doomed system dominated by Satan the Devil." Watchtower Sept 1, 1989 page 19.
8. According to the Watchtower, anyone who dies at armageddon at the hands of Jehovah, will have no hope of a resurrection to life on a paradise earth. With regard to the coming 'great tribulation' and God's day of judgment, the Watchtower says this, ' Christendom’s clergy are lawless in that they have misled millions by promoting teachings, holidays, and behavior contrary to the Bible. Like the religious leaders whom Jesus condemned, the modern-day worshippers who are part of “the son of destruction” face destruction with no hope of a resurrection. (2 Thess. 1:6-9) ' Watchtower June 15, 2008, Article: ' Things From Which We Must Flee ', Subtitle: ' A Future Wrath From Which to Flee ', par 7
9. JW's believe there are only two choices, God's organization the Watchtower, and Satan's organization everyone else. It is believed that Satan's worldly organization, i.e. human institutions, governments, leaders of false religions, and their worshippers, will perish at the hands of Jehovah, so that Jesus can rule the earth for a 1000 years and restore it to a paradise. During that 1000 years, all the dead will be resurrected regardless of their sins and given a chance to earn everlasting life if they are obedient for 1000 years. If they are not obedient, Jehovah will annihilate them forever with no hope of a resurrection again. WT, Aug 15, 2006, ' Questions From Readers ' Question: ' After the final test at the end of the Millennium, will it be possible for humans to sin and die? '
It is believed that only those who call upon the name of Jehovah and follow his rules as explained by the Watchtower, have any scriptural hope of surviving the great tribulation and God's day of judgment at armageddon. However the organization admits that Jehovah is the final judge. They cannot predict who Jehovah will save. Therefore it is possible that some Witnesses will not make it through armageddon. Witnesses believe that just like in the days of Noah, only a few will survive. Satan's organization will be destroyed forever and Witnesses will be judged by Jehovah himself as to whether they're worthy or not. If a Witness does not survive armageddon, they have no hope of a resurrection to life on a paradise earth. They will remain dead forever.
Unfortunately this doctrine is troubling for JW's. As they wait for armageddon and contemplate all the sins they've committed, some wonder if it would be better to die before armageddon. That way they would be guaranteed a resurrection to life on a paradise earth, no matter how many sins they've committed. As long as they're alive they must work hard for eternal life and follow many rules. If they secretly break some of the Society's rules or displease Jehovah in some way, they might not survive armageddon. That would mean eternal death, no matter how many sacrifices they've made for Jehovah.
10. JW's believe they must do 3 things to earn the prize of life on a paradise earth, as summarized in this article. See WT, Nov 1, 2008, Our Readers Ask, - Do Jehovah’s Witnesses Believe That They Are the Only Ones Who Will Be Saved?
Most JW's are only concerned about surviving armageddon. However that's just the beginning. Even if a JW survives armageddon, obedience is required for the 1000 years after armageddon and for all eternity. WT, Aug 15, 2006, ' Questions From Readers ' Question: ' After the final test at the end of the Millennium, will it be possible for humans to sin and die? '