Class “B” motorhomes are van conversions, and always in demand. Van conversions are smaller, easier to drive, and can go places that larger motorhomes cannot. They only sleep 3 – 4 comfortably. You recognize a Class B because it looks like a large van or delivery van with a roof ac.
The class “C” motorhome is the workhorse of the RV rental business, comprising a vast majority of motorhome rentals. The class “C” models are generally designed for families and quite often offer more sleeping capacity than class “A” motor homes. They have driver / passenger side doors for easy access to the cockpit. They are easier to maneuver and have decent mpg. Most are built with a gas engine, but some newer models are coming out with diesel engines. You recognize a Class C RV because of its cab-over design.