We use a dolly for flexibility and to save some $'s. I still have my mid-life crisis '97 Sebring convertible and can't seem to part with it. We tow it with a Mastercraft 80THDSB with surge brakes and can handle anything that our DP can pull. It is also saving us from spending the $'s necessary to buy a vehicle that can be towed 4-down plus the additional costs for a base plate, tow bar, toad brakes and re-wiring the lights (plus I can keep the convertible!!!). Currently in FL and heading out to PCH this summer and then Route 66. No better places to have a rag top.
I timed the difference for me hook up the car vs a neighbor going 4-down. It was about 15 mins since I use the safety chains and have to get up under the front end to hook them up and need to use some 2x6's to keep the front cowl from catching on the dolly, otherwise the process is fairly smooth.
So far we've saved $15000+ (used SUV plus towing equipment) otherwise we might be towing 4-down.
2012 Sportscoach Cross Country 385 DS Freightliner XCR w/ Cummins ISB 6.7L 340 hp
2009 Saturn Vue, Blue Ox Alpha, RVi Brake 2