You pay for what you get for, period. If you live in an area that T-Mobile has good service and as well as not go out much to concerts/sporting events, then go for it.
I've had T-Mobile for a bit over a year and would not recommend them. Drops calls all the time. I haven't noticed any particular geographic difference, but I spend most of my time inside the loop. I had bolted to T-Mobile to get away from AT&T; looks like I didn't know how good I had it.
T-Mobile is liquid garbage. We've been with them since their Voicestream days. Your phone will say "4G". You will be in an area "blanked by towers". You will not have data. Their peak speeds are great, it's the consistency that's the problem. As soon as our contract is up, we're GONE.