I use a Garmin Nuvi 465. I programmed our heigth, weight, and length. In 10 months of use it has been great. Kept us out of a traffic circle in MD that would have been a disaster. Warned us about a low bridge that tunrned out to only be low in the break down lane.
It also give us a choice of car, truck alone and truck with trailer. I did not do any comparative research on the Rand McNally one. Garmin offered us $75 off a new model because our Street Pilot was no longer being supported.
2007 Freightliner M2 Mountain Master (will work for fuel!)
2006 KZ New Vision Sportster
former 2006 F250
former KZ Sportster 29p
former 1995 Coach House 192TB
Live long & prosper