I have certainly looked at these "maps", and the major players each "claim" about the same nationwide coverage.
Not so. You must not have looked at the coverage maps for the same carriers as I did. The only two I really looked at were Verizon and Sprint/Nextel. Those two are not even similar.
Both the maps and my experience on the TA and other tours as well as other trips agree that Sprint's coverage is awful unless you stay close to the interstates and Verizon's is pretty good, but not perfect. As far as I noticed, the only place on the TA where we didn't have a signal with Verizon and other folks did with other carriers was part of Idaho (the Riggins area).
Verizon is hard to beat in this regard. Check out a recent thread on the crazy guy forum at: