Read about the Good Sam GPS in the latest "Highways" magazine so checked it out at Camping World. Saw the Magellan RV9165T-LM. Seemed to have the same features particular to RV's but with free lifet...
The dezl for the Motorhome Product name: dezlâ„¢ 560LMT
The nuvi for the Dinghy Product name: nüvi® 465LMT
The mapping info for both units have had brainfarts, and is not as accurate as previous models. I am assuming it is the mapping input used for all GPS units.
Using any GPS requires some planning ahead, about general routes, etc. On long trips I use both the GPS and Microsoft S&T to compare routes.