It's uncommonly good. Definitely not to be missed. Despite it's 80% positive rating on rottentomatoes.com, some critics said the plot was silly. I thought it had quite a strong plot, with few holes, and a great story. The great f/x are icing on the cake.
No, I'm kidding, I like them both. I haven't seen X2 yet; I'll have to find time to go see it, between AP exams, the upcoming Disneyland trip, M:R, and prom. I think I can squeeze it in at some point...