We've had Verizon & ATT phone service for a number of years now. There have been cases where one service isn't available and the other is. We use ATT as our main phone for all business and long conversations since we have about 6K of rollover minutes. Verizon is our backup with limited minutes.
We have both services for a number of reason that aren't relevant to your question. If we had to pick one service, it would be ATT. We travel extensively in the US from coast to coast and everywhere in between.
We do use the phones as phones, not cameras, GPS, texting, etc.