As a Jew I have two main reasons (and many, many lesser ones) for being interested in Christ narratives. In order of importance, those two are:
1) Not having grown up with the story of Jesus too-heavily ingrained in me, it's easy for to me to see it as a little foreign and alien, and therefore fascinating (and a good story).
2) I am always interested to see the ways in which different tellings of this story depict my own people.
Also, I found this beautiful copy (every page has unique border illustrations) for 6 bucks!
I actually wrote a paper that was largely about Ben-Hur, but I still haven't read the whole thing. Can't wait to do that when I have the time.