Granted it is the first and only GPS we have used, but the 7720 has worked well enough for us, but has a number of flaws.
On the plus side..
It has a large point of interest database including tons of campgrounds. Public and Private. Most of the time we can just select where we are headed and don't have to insert an address. Waypoints are easy to use and enter. We don this a lot for things like grocery stores on the way to a new site. The screen size is nice and easy to read at a glance. Always seems to get us where we want to go and never gotten us into a tricky situation. I also like it shows the current speed limit.. and man is that accurate.
Long startup time, plus having to accept the damn terms every single time it is powered on.
It freezes every once in a great while.
The screen is hard to read in sunlight.
We hate the voice so we turn it off, but there is no visual indicator to which side of the road the destination is on.
I wish there was a faster way to switch between RV and Car mode, plus a visual indicator of which you are in. We leave it in RV mode, but then it will never just tell you to make a u-turn, it will take you down side roads in order to make a u turn (handy with trailer in tow)