Over the last 2 days and several years I've made a few observations. This specifically covers I-69 in Michigan between flint and Port Huron (Blue water bridge)
As of as recently as last summer when I'd make that trip every 2 weeks with the motor home there were several "Dead spots" t-mobile wise. (I stream WTWW.US-transmitter 2 when traveling)
last two days, now that they claim they have FULLY merged Sprint towers in, I had to make the trip twice in my car for Medical reasons.. NOT ONE DROP. I did have a couple spots where it seemed to pause for oh. perhaps half a second. but it did not drop (I assume tower hand offs).
So.. Very pleased with the new coverage