Wow. I never saw this coming! T-Mobile may yet become the numero uno USA carrier. Take a look at their future coverage map if everything goes as planned. https://newsroom.t-mobile.com/news-and-blogs/tmobile-spectrum-auction-win.htm
Do you even need to ask? I don't expect that'll happen overnight either, IMHO we won't see any phones with 600MHz support till 2018 at the earliest.
Dish keeps buying spectrum and they aren't doing anything with it: https://www.bloomberg.com/politics/...ion-spectrum-spree-ergen-buys-himself-options
If they can get western NC covered adequately (specifically the Boone area) I'll probably switch back to them. I moved back to Verizon for that area.
They do appear to be increasing their coverage. About 5 years ago when I had T-Mobile, they had Chicagoland covered well, but if I had work in northwest Indiana, I would get 1 or 2 bars and if I walked into any building there was no service. A couple of years ago when I had T-Mobile, one of the first things I noticed was they suddenly had northwest Indiana covered.