The biggest disadvantage that I have found is time and work. With 4 wheels down when arriving all you have to do is lift the tow bar off the ball and you are good to go. With the dolly undo the straps (not always the easiest thing to do) then SLOWLY back the car down the ramps. When leaving you do everything in the reverse order. figure with a lot of practice 1/2 hour to get on the dolly and ready to go. Must check straps at every rest stop as they tend to stretch out. The dis advantage of 4 wheels down is initial cost, but after using my dolly for four years I think I should have paid the cost.