I think at the end of the day it's what appeals to you. AT&T, allegedly from the blogs I've read, has faster LTE and 3G/4G. Verizon has the better plans and pricing. I have an AT&T preorder currently but am strongly considering changing to Verizon. 14.99 for 250MB? I mean seriously, AT&T lets be a little more realistic.
Also if you internationally, I don't think you'll have LTE. Should be a moot point. Meh, I still have no idea what I should do.
How does verizon have better plans when you get less data for the same price on the $30 plan?