My brother was on Sprint recently. Their coverage is very slim here in E Ky. He was traveling back and forth to Tenneesee due to work. His wife's phone stayed in a roam area and they eventually cut that phone from the contract. I have line of sight to a Sprint tower from my house so I'm good to go. Althought it will be after the next ice age before I get 4G here
From what I've seen Sprint, seems to let some slide and not others.
I have a friend on Verizon who roams most of the time here and has had the contract for a year at least I think.
I can't wait to hear some feedback on the EVO when it hits