I bought a Garmin 760RV a few years ago when we went from a TT to a Class A MH. I probably would not do so again.
The very first year we used it, it took us on a long roundabout drive, I assume to stay on US and Interstate highways, rather than use the more direct FL state highway that saves an hour or more. From that point in time, I have also used the TomTom from my truck alongside the Garmin, as well as consulting the FMCA Road Atlas before each day’s drive.
The things I like best about the Garmin are 1) the larger 7-inch screen, 2) it has Bluetooth for hands-free cell phone usage if I get an incoming call while driving, and 3) I can download GPS coordinates from RV Trip Wizard that leads me precisely to the entrance of each campground. Street addresses are sometimes very unreliable in my experience with GPS.
Around home in the high mountains of WV, all GPS’s can be very unreliable as they don’t seem to understand mountains and may lead one over roads that are impassible to most motor vehicles. Better to use a map and some judgment, or simply ask a local for the best route.
Wayne