I bought the Magellan and hated it. Took it back to Camping World and got the Rand McNally. Love it.
My best RV buddy loves the Magellan for use in his 40's Monaco.
I have an older smaller Garmin with live traffic which we use alongside the Rand for traffic information and follow its directions when it tells us to detour for traffic.
The choice of a GPS is largely which interface you like.
One of the best features of Garmin in my opinion is their live traffic updates. Beats Rand hand down. Don't know about Magellan or Tom-Tom.
All the GPS manufacturers use basically the same data from the states for routing and road suitability. Rand and Magellan do small updates frequently which is a very good thing in my opinion. Their system is designed to update things like low clearance, bridge weight limits, POI, speed limits frequently.
Garmin requires a 2 GB map update a couple times a year to update such info in one massive update.
Regardless - never ever completely trust a GPS to guide you. They are ADVISORY - not mandatory. You need to know where you are going.
In my experience Rand and Garmin both offer good lane directions for upcoming freeway intersections. Don't have experience enough with Magellan or Tom-Tom to know about them, but suspect it is the same.
Full-Time 2014 - ????
โNot all who wander are lost.โ
"You were supposed to turn back at the last street."
2012 Ram 2500 Mega Cab
2014 Flagstaff 832IKBS TT