Never had t-mobile, but I have had AT&T for a little over a year and havent had a single problem with them, the roll over minutes work great between me and my girlfriend. We had verizon before hand and I will never go back to them, every month they were charging us overages for $100's. But I have been pretty satisfied and happy with AT&T.

Our plan is 1100 min, unlimited text, data plan. I think we pay 150-175$ a month both of us have Iphones.