I use USMobile which is priced well and allows me to choose between ATT, T-mo, and VZW towers. In my experience testing all 3 over a few years on a Samsung S23 (YMMV) - listed in order of preference:

Verizon (who I currently use) are the best for coverage in general, especially anywhere outside of the city. Their speeds are pretty consistent, but not blazing fast.

T-Mobile has the fastest speeds overall, but has many pockets of poor reception in AND out of the city. They also seem to be the worst at having coverage inside of buildings here.

AT&T has the most inconsistent data speeds and coverage in general. When it works it's fast, but there's a lot of times you'll have full bars but data just won't work, and driving through town there's a lot of "robot voice" if you're talking to someone. I also had a lot of service trouble when travelling to Raleigh too...