nau1977, although it pains me to say this, I would not recommend that you get T-Mobile at this point.
I used the coverage check tool
http://www.t-mobile.com/coverage/?class=coverage
Grant it, a T-Mobile phone will work there because we have roaming agreements...
Grant it, we have plans that include FREE roaming
However, since it is not a T-Mobile market you would not get the full benefits of being a T-Mobile customer. If a tower was to go down in that area, there would be nothing that T-Mobile could do about it since it is not T-Mobile's tower. If your phone was to start losing signal, there would be no way of knowing if the problem was being caused by your phone or by the area you live in, you'd have a more difficult time than most others before getting a resolution. You would also have to check your voicemail from any phone other than your own mobile phone (or you'd have to wait to check your voicemail from home).
Another thing:
When you are on the T-Mobile network, it takes only a few hours for your minute usage to update into our own system.
The minute messanger feature, #646#, would be terribly inaccurate because T-Mobile would not know your minute usage until the roaming partner tells us. Therefore, it would be very hard for you to track your minutes usage.
I'm sorry if this is disappointing, but I'm here to help you.
The companies you mentioned all have 2 year contracts. So hopefully we'll have coverage in your area 2 years from now. I saw on the coverage map that T-Mobile has towers in the 73527 zip code, so I hope we expand out to your area.
Good Luck