Consumer Cellular resells service from AT&T and T-Mobile, as does Mint. There's no reason to think that there would be any speed or coverage differences as they are reselling the same service. If those networks are strong where you need to use your phone then you should be fine. They are both non-existent where I live, and Verizon isn't much better.
Tracphone, now owned by Verizon, mostly uses the Verizon network and is converting users to that system.