We just found an RV 660 LMT on sale at Cabela's for a bit under $300, and used it for the first time on our last trip of the season.
So far, I love this thing! Great POI list, beautiful screen, intuitive to operate once you learn the basics. I got the Smartphone Link app, which gives better traffic and real-time weather forecasts and radar. I also added another campground POI database, which was very simple using the Garmin POI importer tool.
I found the navigation to be quite easy to follow, and I really love the "lane assist" feature. Elevation charts were interesting, and the traffic seems to work quite well, especially via the Smartphone Link app. Weather requires the app, BTW. It can be a bit slow to load, but that didn't cause any headaches. Very nice to get the temp right on the home screen, and I'll appreciate the severe weather alerts.
I haven't used the hands-free phone functionality, but I have used the "voice command" features. Reviews are pretty mixed about this, but I had no issues and thought it worked pretty darned well if you speak clearly and strongly.
As with any new GPS, do follow the strong recommendation to immediately run a map and OS update with the "Garmin Express" tool as soon as you take it out of the box. In case you don't know, the "LMT" in the model name indicates lifetime map and traffic updates. I would not buy another GPS without this.
Safe travels.