Besides say 'corporate plans' where your company pays for your plan on Tmobile, how is it better than AT&T? From what i hear, you lose visual voicemail, and you don't get 3G data. so why switch? I've never used Tmob.. so this is an honest question, not to spam/troll. I'm hoping for some technical answers. Finally, if you just got the iphone 4, if you use Tmobile, don't you still have to pay AT&T for your contract of 2 years? Just wondering how some people got out of that. Thanks!