T-Mobile is fair in J'ville. Spotty coverage downstairs at my house, but fine upstairs. It works great in large metro cities and no so well in the suburbs. Surprisingly, it worked great in North Ft Hood, Texas! Unlimited data was the shiznit and 14 GB of tethering meant I was always able to use my Surface Pro on the internet. I kept streaming to my phone.
Overseas, particularly in the sandbox, the T-Mobile international plan shines. I get the same unlimited data and 14 GB of tethering each month. Texts are free. Calls to the states are $0.20 per minute. Every country I have been to in the sandbox has provided instant service getting off the plane through T-Mobile partners.
Oh yeah, NAS Jax and to some extent, Cecil Field are cell phone black holes; especially for T-Mobile.