I wanted a add a line for my kid on AT&T, and the customer service person I worked with had a big grin... telling me no problem, but they would take away my GFUDP. They played this cat and mouse game too long with GFUDP customers, so I went to T-Mobile. Honestly, my coverage was better with AT&T, but T-Mobile hasn't completely sucked for me. Like AT&T, they have a data cap... but T-Mobiles cap is 32GB... before they "may" slow down data in congested locations. I've never seen any signs of throttling, and I average +-50GB/mo. I get the push notification that I've gone over 32GB everyone month about 2 weeks before my billing cycle ends.
Yes, AT&T has better coverage... but T-Mobile doesn't suck in my location. I can remember when AT&T coverage sucked when Verizon was doing their "Can you hear me now" commercials. Like AT&T, T-Mobile is making moves to improve... looking forward to their 600 MHz LTE network rollout... accelerating network expansion in rural America. AT&T has great coverage now... but it wasn't always like that. I've contemplated going back to AT&T... but my last encounter with their customer service leaves a bad taste in my mouth. Plus I keep thinking as a long time AT&T customer.... AT&T got better over time... T-Mobile appears to be going that direction with their 600 MHz LTE network rollout.