HI, I decided to switch to T-mobile from AT&T. I have my wife's iphone 5s which is 6 months into AT&T next plan. I plan to pay-off $400 and get it unlocked from AT&T and initiate my T-mobile switch. If AT&T unlocks my wife's iphone 5s after i pay-off the $400 remaining balance, Can i take it to T-mobile store and use their SIM card to work in the iphone 5s? Will the 4G LTE band also work with T-mobile? Has anyone did similiar switch from AT&T to T-mobile with their iphone? I need your suggestions pls. thanks in advance.