Nexus 4 to replace AT&T One X?

So, I got a One X on AT&T on launch day, and I've had it for a while and love it, but the screen cracked about a month ago, and I need to replace it somehow. I'm liking the looks of the Nexus 4, but is it really worth upgrading to over the One X? I am nothing short of in love with stock Jelly Bean, and clearly performance will be better (S4 Pro vs. S4), but things I'm worried about include relative screen quality, build quality, and lack of LTE. I'm in an LTE market (Boston) and really appreciate the speeds it gives me, but it's not essential.

So, help me out here. $300 off contract is pretty enticing.