Christians love to claim that they are more moral because of being Christian, which of course is debatable. The U.S. is a "Christian nation" and yet it has a higher murder rate than Japan, where Christianity is a tiny minority. When you point out to them that once you've accepted Christ as your "savior" there's no reason not to sin, they cite Jesus' teachings about how to live, but there is no punishment for not following those teachings. You're supposed to do those things because you want to once you've been "saved." But good works can't get you into heaven; only believing in Christ can, supposedly. So Gandhi is in Hell and Hitler is in Heaven. How is that moral?
If I were to suddenly believe in an immortal soul and decided to align myself with a religion to protect its future, Christianity would be the least appealing choice for these reasons:
Eternal reward / punishment. Eternity is a very, very, very long time. And you have at most 100 or so years to get it right here on earth. Why should someone be rewarded or punished with eternity for a finite life's decisions?
"Grace." Being a Christian isn't necessarily a matter of choice. A lot of evangelicals believe their religiosity is a gift from God. So not only do they get off scot free for eternity for being believers, they didn't even make the right choice on their own and yet they get the credit for it.
Predestination. In Calvinistic Christiantiy God is believed to to have chosen who gets the gift of "grace" in advance. Curiously, he seems to grace only people who were brought up in Calvinistic churches. Very convenient. Even non-Calvinists believe in some predestination if they consider the prophecy claims of Jesus to be true. In that case, Pontius Pilate and the Jews who demanded Christ's crucifixion were merely carrying out God's will.
Justice denied. If you sin, then you are forgiven because you believe you have been forgiven, your victim receives no redress for what you did to him/her at all. If the sin can be wiped clean, why not the harm done by that sin? There's nothing in the New Testament that shows any concern for the victim of a sin. If you murder someone then "accept Jesus as Lord and Savior (hallelujah)" their family still suffers that loss.
If Christianity were to start as a cult today, it would be so thoroughly laughed at and discredited it wouldn't stand a chance. It only survives today because of childhood indoctrination and a long tradition of rationalization (oops that's called "apologetics"). If there had never been any religion before today and you suddenly had to pick from among the ten or so biggest religions, choosing Christianity would be selfish and amoral. There's nothing noble in being a Christian.