I currently have a Nexus 4 on Straight Talk with an AT&T sim card. The data speeds with the AT&T sim is a lot slower than when I had the Tmobile sim. The reason why I switched from the T-mobile sim to the AT&T sim was due to the fact that I couldn't get service in the building where I work. Coverage everywhere else was fine. My question is if I were to switch to T-mobile post paid, would my service be any better than with Straight Talk T-mobile or would it be the same?