This is a loaded question which will get more loaded answers. :) Everyone has a different opinion and experience.

I have been with T-Mobile since they were Voicestream. I bought my Nokia 6190 in 1999 when it was hot! I have never felt the need to switch. They have good enough coverage here. No contracts. I can get new phones whenever I want. I can pay for them however I want. I have a 2 line plan with 6GB data each line, which is more than enough. $89/month. You cannot get that deal anymore unfortunately. :( I could have 4 lines unlimited everything with free Netflix for $160/mo. Not bad. But my kids do not need phones yet.

I have friends who love VZW and friends who would murder VZW if they knew they would get away with it. Same with Sprint, AT&T, and even T-Mobile. Different strokes for different folks. Get what floats your boat. Try them all on their pre-paid plans for a few months and see which works best. Then make an informed decision.