I've towed our '05 Odyssey four down and on a Demco KK-460. It's slightly easier to tow four down, but not much. On the dolly I don't have to worry about going through the gears with the engine running, nor transmission damage if I forget and do it wrong. don't have to worry about CV joint damage, nor running the battery down. I do have to find a place to park it and manhandle it around. Only once have I had to park it away from the MH. Plus I can tow either our Odyssey or Civic or almost any other front wheel drive vehicle.
Four down you have to run through the gears correctly, leave the key in and turned on, be sure to turn off the radio and heater.
Hook up and disconnecting is about the same time.
Frankly it's a toss up due to the worry about transmission/CV joint damage four down vs the slight extra work for the dolly.
The dolly tracks the MH better as four down it cuts the corner more so I have to remember to square the corner more. The dolly wheels steer and it really follows well.
It alse seems that it tows easier on the dolly than four down, maybe because the trans isn't being turned.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '05 Odyssey