I haven't had any issues with tmobile coverage (that wasn't also a problem with verizon) in well over a decade now. Hell it even worked well in the dense hilly jungles of burundi. Verizon customer service was so bad before I switched I swore them off for life....

The single place I noticed verizon gets coverage and tmobile doesn't is three levels underground in a concrete parking garage.

Coverage is very specific to your situation. I've had basically no coverage on Verizon in offices in the Bay Area where T-mobile worked fine while colleagues could only get Verizon at home.