As a former Motorhome owner use to less than 8 mpg at 55 mph, I believe a Bigfoot
is a more economical ride. Theirs a big difference in fuel costs between 8 and 12 mpg. The other problem with a motorhome is that after "n" miles that when the engine/transmission's dead you have major expenses. With a fiberglass trailer you simply update the tow vehicle.
As well Motorhomes, even the best of them, are not structural wonders even with great care except for maybe the Born Free; they seem to be solid rigs.