We use the Garmin 760 RV LMT. Customizes to your specs. We didn't go for the extra add on package for gas mileage etc since all of that is already in the Berkshire. We previously used a Magellan RV gps that was awful. The 760 has a quick response touch screen. We've used it for close to 3,000 miles so far without any problem. Kept us on all the right roads. And if you do miss a turn it re routes you without the annoying "recalculating" message. And the traffic alerts were spot on, warning us of where it was and what our expected delay time would be. Also advises you of upcoming speed limit changes or road conditions.
Doree and Neal,
2011 Berkshire 390QS
2011 Honda CRV EXL
2013, 107 days; 2014, 190 days, 2015, 184
2016 134 so far