I said the major source of contradictions is in the four gospels. That is about two issue that are of major importance in Christianity:1) Christology [what does one think about Jesus], 2) the other is mitzvot.
On the other hand I also said it is not good to downgrade someone else's religion. Everyone thinks their is the best.
He asked if I had been born to two parents one Jewish and one Christian, what faith would I choose? I said, "If I could choose any parents in the world, I would only choose my own. I am very happy with the way the raised me--Jewish [Reform-- but with a traditional slant].".
I forgot the whole discussion but also he asked which is better Judaism or Christianity. I said, "I go by what Reason requires. Ah but my reason is faulty? So what. There is no better path."
That was my first answer. He was not satisfied and then went to question two, and after that to question 1. So I am not writing this in order.
[My thoughts were that this is really a matter of group identity. Torah is my path and I think that this is good. I think when I see people fishing for arguments against other religions that that is not a positive thing.]
Later on the way home I thought to myself that there is an essential connection between path and human good or evil. We find paths that encourage people towards evil. And we also find paths that encourage people towards what simple common sense would be called good and just. So even there are bad people on all paths and good people on all paths still that does not mean the paths themselves are equal. So there are religions that it is worthwhile fighting against. Some are so bad that they deserve to be shunned. Some cause so much damage that you have an obligation to warn people against them.. But not all. Some are in a grey area with some good things and some not so good. Fighting them seems to be dumb. You are likely to end up causing people to throw out the good with the bad.