In the past 7 years, more people have dropped landlines for cellular only. Multiply the dropped land line by average 2.5 person household and you get an idea of the massive burden shifted to the cellular carriers. Just like more devices reduce you bandwidth on home internet, more cell phones divides the cell service.
Ive been back and forth between ATT and Verizon. Most recently back on Verizon for July because my ATT signal dropped at home again. both are equally bad at my home.
I bought a microcell and a cell booster for my car and my problem is resolved. Switching to a carrier with far less coverage is surely not a solution, so I laugh at the idea Sprint or T-mobile covers you and Verizon does not. Better do your homework before you make an expensive mistake.