blurb from this site
http://www.inplainsite.org/html/pre_tribulation.html
"Why not post-tribulational?
1. The conquered saints: In 1 Thessalonians 5:9, Paul writes "For God hath not appointed us to wrath ...." But at the midpoint of the tribulation, Revelation 12:12 says "... Woe to the inhabitors of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time." Revelation 13:7 says of the Antichrist, "And it was given unto him to make war with the saints and to overcome them ...." His authority lasts for 42 months (Revelation 13:5). Also, Daniel 7:25 says the Antichrist "... shall wear out (oppress) the saints of the most High, and think to change times and laws: and they shall be given into his hand until a time and times and the dividing of time (3 and 1/2 years)." "... he shall destroy wonderfully, and shall prosper, and practise, and shall destroy the mighty and the holy people." (Daniel 8:24). "... when he shall have accomplished to scatter the power of the holy people, all these things shall be finished." (Daniel 12:7). The Antichrist can only "destroy ... the holy people" if the tribulation saints are not members of the true Christian Church of this present dispensation. The saints in the tribulation are people who become believers after the rapture of the Church.
2. Sheep and Goats: We know from Matthew 25 that Jesus Christ will divide the sheep on His right hand and the goats on His left after he returns. Matthew 25:31-34 says, "When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory: And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats: And he shall set the sheep on his right hand, but the goats on the left. Then shall the King say unto them on his right hand, Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world ...." Then in Matthew 25:41, "Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels ...." Now if all the believers were raptured just before Jesus Christ returned, there would be no sheep left on earth to divide, only goats.
3. Who would populate the millennial kingdom? We know that mortal believers will live in the kingdom. But if all the believers would have been raptured, thus immortal, and all the unbelievers would have been killed. There would be no more mortal believers left to populate the kingdom.
4. Resurrection of tribulation saints: After Jesus Christ's return in Revelation 19:11-16, Revelation 20:4 tells us about the resurrection of martyred tribulation saints who did not receive the mark of the beast, "... they lived and reigned with Christ a thousand years." If the rapture had occurred just before Christ's return, they would have already been resurrected, and could not be resurrected again."
-------------------------------my thoughts
Either case I know I am saved and spared from ultimate torture. I seriously think people will be quited sobered up when they find a mass amount of people missing. Many churches empty, children & babies gone..perhaps they were on to something? Yes people will get converted after the rapture. But they will still have a rough life. God forgives but doesn't relieve us of the consquences of our actions.