Even if they’re inaccurate, the coverage maps do tell a story. Out west on t-mobile maps you often see circular coverage arcs and then you know they just have one tower somewhere and project coverage out to the max possible range, which you can’t achieve most of the time anyway. Not to mention tower overload, etc. I travel quite a bit through the western deserts and mountains and Verizon coverage is just better than the others. Then AT&T and forget T-Mobile. But if you stick to the interstates it doesn’t really matter that much. In other parts of the country it may well be different, I just don’t know.
WRT costs,I use US-mobile’s “super-LTE” SIMs, which are on verizon. 1GB of data costs ~$14 incl taxes and all. It’s easy to change plan and to add extra data if I run out. I’ve been quite impressed with the customer service, they’ve actually helped each time I’ve chatted with them, which is a completely new experience for me…