1. Christianity ended slavery when modern 1800s interpretations called for it. Islam condoned slavery and ISIS brought it back.
2. Islam is a violent religion, with calls to conquer the world until all submit to Islam as either Muslims or Dhimmis (second class citizens). Don't bother quoting the Medina period verses of get along with fellow monotheists - the concept of abrogation in Islam says the violent verses calling for death to the infidel override the early ones, just as calls for "don't get drunk" are overridden by the "no alcohol ever". And unlike Christianity, the right to kill the infidel led to Sunni-Shia violence within 50 years of Mohammed's death, while both groups kill Almaddhi and Sufi. Christians don't kill each other in the name of Christ barring some political wars.
3. Christianity gave women inherent respect and status even in the early church. Conversely, the Koran says women are half the worth of a man, he has the right to beat her for not obeying him, she cannot get into heaven if her husband isn't happy with her, and 90% of honor killings on the planet are committed by Muslims. On the basis of women's rights, Christianity wins.
4. Christians are debating whether Christians have to make a wedding cake for homosexual weddings they consider blasphemous. ISIS is killing homosexuals per the Koran, as do Iran and Saudi Arabia. Secular liberals are insane for acting as if not participating in a gay wedding is horrible but ignore Muslims killing homosexuals. Ditto ignoring the common practice in the Muslim world for executing or jailing rape victims for the crime of having sex outside of marriage.