My answer is "It depends". We are not full timers and the dolly has served us well. Since I have never towed four down I suppose my perception is its no big deal. The one comment I agree with is the weight of the dolly is sometimes hard to move around. I do have a lighter weight dolly so its not too bad over all.
Now the reason for my 'It depends" answer is the initial cost of four down can be quite expensive and unless you are full timing it just may not be worth the cost. To setup my 2007 Chrysler Town & Country Touring for four down towing it would have cost me $3800 as I would have needed the tow bars, brake system and an oil pump installed. Buying my
American Car Dolly cost me about $1200 when I purchased it. If I were full-time I would not have gone the dolly route but rather would have setup for four down towing.