I actually have a copy of Xillia 2 but never played the first - should I play it anyway? I've heard mixed reviews from friends.
Yeah, definitely play the first. Good story, great characters, really awesome battles. Xillia 1's colosseum is close to maybe my all-time favorite arena/colosseum in any RPG. Really insanely fun (even if it is WAY TOO HARD when you first unlock it).
I don't disagree about much here, but Xillia 1 is very easy to dislike after a while. You may find yourself wanting to not bother continuing into 2 after a playthrough, which would be very sad as I find 2 to be very much the better game, but 1 is still a great game itself.