I know there have been negative comments, but I have used my seven inch Rand-McNalley 7725 (Good Sam) for two years and 8,000 miles and never had a problem. I like the ease of entering locations, the low tunnel warnings and the large easy-to-read display. There are a lot of initial settings specific to the individual RV and the type of roads desired. Once I set those I had no problem with questionable routing. There is a learning curve. Destinations are entered differently than in the Garmin I use in my car. Now that I am used to the RM I like it better than the Garmin.