We've had the Good Sam branded Rand McNally 5" for 3 years now and use it constantly. I like that you can switch routing modes from "car" to "truck" like routing, set your RV height, turn warnings (curves/hills/state borders/speed limits) on and off. It is extremely customizable but takes some experimentation to figure out what some of the options actually do. I use it even when not towing because it provides speed limit warnings--you can customize how far over the posted limit you want to go before the bitchin' starts--this is great if you are a leadfoot. Especially helpful in California where the speed limit is 55MPH for any vehicle towing or with more than 2 axles. A violation is $300-400 trust me. Another big positive is the ability to download trip plans and custom POIs from the Good Sam trip planner website. This is huge since you can sit comfortably at your desk or laptop and compare Good Sam info with other sources (Google Maps, USFS websites, and of course RV Park Reviews.) One negative is that their map updates can be months or years behind for new roads. They update their construction zone data very frequently but I suspect that and new road data comes from state agencies which may or may not provide timely updates.