In the Garmin world you have the 770 LMT (Lifetime Map & Traffic) for about $400 or the 660 LMT which is an inch smaller (6" vs 7") but uses the same operating system and is $150 cheaper.
In the Magellan world you have the cheapest entry with the RoadMate RV9145-LM at only $120 on Amazon, but may not arrive before Christmas.
You also have the RoadMate RV 9365T-LMB at $326 and the RoadMate Pro 9165T for $420, neither of which have good reviews on Amazon.
I have the Garmin 660 cuz I'm cheap and although it works as well as any of my other 3 Garmins in my cars, I have been underwhelmed with the RV specific features.
Regardless of which one you chose you must remember it is just one input to your navigation so don't rely on it blindly. Get other inputs from Google Maps, Waze, Road Atlas, etc.
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad