Please note that the important factor in the post you quoted was
"'affordable' ... DATA" .

Yes, T-Mobile's coverage area is spotty in rural. That's true of any
GSM service in this country. And in some locales (WV for instance),
coverage of ANY type of service is spotty.

But back to the DATA issue. T-Mobile is something like $30 month for
unlimited. Almost all the other companies are in the $50 or more  range
for unlimited data.