I've had T-Mobile for 2 years now. I live on the South side of Chicago. I've witnessed first hand The improvements on their network. I also have unlimited data which is keeping me from going anywhere as well. To those debating the switch, I say go for it as long as you have coverage at home and work.
I was an AT&T customer for about 15 years, but this year I switched to Verizon. I live about 20 miles south of Portland, Oregon. Verizon LTE is 4-6 times faster than AT&T in quite a few places. They've got coverage in most of the AT&T dead spots that I knew about. There are a few spots where AT&T worked fine, but Verizon doesn't. I have heard horror stories about T-Mobile where I live, so they unfortunately don't get a chance.
At least when I was a customer of T-Mobile they offered a free way to try their network. You would get an iPhone 5s I think it was and you get to try their service with no strings attached. All you need to do is allow a hold of $800 or whatever it was and give it back in 2 weeks.
Well, being that I have unlocked Verizon phone, I could just sign up for one of their pre-paid plans and try the service out for a month.
Either way I know the coverage isn't as good in outlying areas, so I'll stick with what I've got.
😀🙁Other: my carrier is not available in third-world countries run by corrupt billionaires.
That's up to you but I would give it a try IMHO. Got nothing to lose. I loved Verizon but they got so expensive for me.