I see that this is actually rather late since you seem to have decided.. but I have T-mobile, and have since I met y'all.
My reception is more than adequate.
I always miss NA's call in the park, or the aquarium, but they do come through.
My down spots are the toll road from SD to Casa Meinke, a few dead spots in my city, but all with major valleys.
The ToT area of DCA.. dont ask me why.
and elevators.
otherwise, I've been with them for... four + years.. no issues.