For what it's worth, I bought a Garmin 760 RV this summer and we used it on a 5K+ mile trip from AL to NS. I like the Garmin format and am familiar with it's use which helps. The coach had a Alpine GPS which I discarded and used the original mount and the Garmin mount epoxied together so it sits in the original spot and works great.
Love the campground feature and only had 1 situation where one wasn't in the data base. Routing kept us away from problems but I ALWAYS look a a map too. 45 years flying helicopters taught me to never completely rely on electronic navigation. Also taught me to use check lists which has kept me out of trouble but that's another topic.