Well if I had to choose between both I'd go with XL. But it really depends on what you use your phone for. I found that once I got a bigger phone it was hard to go back to a smaller screen, everything just looked ridiculously tiny.
I'm participating in a desperate attempt to get a free new phone since mine is on the verge of death. Good luck everyone but hopefully more luck to me though hehe O:-)
I like the black and the silver one. Blue seems a bit too flashy for me. If I get one I'll go with silver because it seems like there would be less fingerprint issues with that colour.