As stated previously, the Garmin RV 660LMT is the current model. Is it perfect? Heck no, but it is the best GPS I have used to date which includes TomTom and the Rand McNally RVND 5510.
Along with the RV configuration of the unit I also like the hands free Voice Activated Navigation and the Active Lane Guidance features of the unit. The screen is much easier to see in bright light compared to the Rand McNally unit I had.
Best advice I can give regardless of which GPS you buy is hook it up to your computer and download the latest maps and updates before you use it for the first time. Also download the complete manual and learn to how use the unit to take advantage of all of its features. The RV 660 comes with lifetime maps and traffic so periodically hookup it up to your computer and update it. And my last piece of advice is never put blind faith in any GPS.