Verizon. When the iPad 3 landed I got a Verizon model to give the company a shot. I know it’s LTE and the iPhone 4S isn’t, but at least it gets me in the ballpark. I was happy enough, and upset enough with AT&T after over seven years of service, that I didn’t mind putting up with switching in the middle of an iPhone cycle and dealing with the early termination fee.
Of course, I assumed that, once I deal with the account switch and paid everything off, I would be done. But you know what they say about making assumptions!