I bought the RVND-7715. I set the height of my RV in at 12 feet (just to be sure to give extra clearance to my 9' RV). It was routing me onto a highway with a 7'10" height restriction with the height set at 12 feet. I contacted Rand McNally and got a stock response and no answer as to why or what to do about it. The GPS went back to the store the next day!
I never plan a trip without doing it on the computer first but there are times when I would like to stray from the route while on the trip, and want a GPS that will not get me into trouble. The Rand was not the one.