I have owned or borrowed Garmin, Tomtom, & Rand McNally GPS's and they ALL have problems. Sending me into empty fields, repeatedly insisting I was off the road and loudly proclaiming that I needed to turn around when I was on a freeway, asking for big bucks for Canada or Mexican maps, etc. etc..
Well, I just finally had it with messing with expensive name brand GPS systems and looked on eBay for a generic. And found there's a bunch of them. What I settled on was a car/truck/bus configurable type, 7" color screen, Mediatek GPS with free maps, supported by an open source community of people who just like working on maps. Free lifetime map upgrades. Mexico and Canada included free.
And the best part was that the Mediatek only cost $49. I just checked and it's no longer available but nearly the same thing is...
7" GPS I've used mine for 18 months now and really like it. The big screen really suits the RV pilots area. I've had it route me around low bridges or away from tight downtown streets several times as I have it configured to consider my vehicle as a bus. All the routes it's taken me on for the last 18 months have been fine.
Since the generics are just as good as the name brands these days (they all use the same maps after all), and several times less expensive, seems like an easy choice.