tow dolly vs. Tow bar

Back in 1982 we bought our 1st motorhome. Scottiemom's driver was a top of the line Mercury Sable. Tried the steerable and turntable dollies, with the ground effects on the Sable neither was a satisfactory solution. Been towing four down ever since with vehicles that were adapted to made towable. Vehicles towed have included, A Madza GLC 5 speed, Dodge Colt 5 Speed, 2 (88 & 93)Ford Aerostar vans with a Remco driveshaft disconnect that I installed, a 1996 Geo Tracker 4x4 automatic, a 2003 Ford Sport Trac 4x4 automatic and now a 2014 Ford Flex AWD. The Aerostars were our favorites, just ahead of the Sport Trac, since all could tow a boat or trailer easily, but Ford quit building both. Do your own research if towing 4 down don't believe the salesman, read the manual. Reason for research... the Sport Trac with the following model years may or may not be towed according to Ford. It was towable, then wasn't, then it was again, then they jumped the curb weight almost 1000#.