I take trips with my buddies each year where we fly to a big airport and drive around 1500-2000 miles round trip from there into rural areas on back roads.
We are a great cross-section of providers with Tmo, ATT, Sprint and VZW. I was the only one with service for the entire trip the last two times (NE states and NW states). ATT was next best. Sprint was the worst and Tmo was next.
My family takes a ~3000 mile road trip every summer. I've only been out of service once or twice in 7 years and those were in rural areas of Alabama or Oklahoma (IIRC).
I wouldn't give up VZW for anything.