As most have stated, four down is easier but more expensive (+/-$2500) and not as flexible as you won;t have base plates on all of your vehicles (if you did the costs go up). If you don't have a car capable of being towed four-down then you have to add the cost of purchasing one. I did it both ways and the biggest issue I had was moving and storing the dolly as it's bigger than you would expect and heavy.