I have Verizon for a few years now. I have very little issues about using it on the lake. The only place I know of that I have trouble is the west Alton area, in front of Sleepers Island.
This year I bought a Treo so that I can access my emails and messenger services. It works great! I can access most web sites, although it is slow. For those who has no cable or phone access but need to communicate on the internet, Verizon WiFi is one way to go.