Originally Posted by AndreyT
The most important step in any car wash is the very first one, when you use clean water to blow off the accumulated grit off the surface of your car's finish. If the abrasive particles were properly removed before the actual washing began, it does not really matter what kind of car wash you use - hand wash, soft cloth, mechanical brushes or anything else. It makes virtually no difference (assuming the washing medium is properly maintained).
You said they gave your car swirl marks? That was caused by the grit that was left on the car before the actual wash began. Under such circumstances, hand wash is in no way better than anything else. I'd even say that you get uglier swirl marks from hand wash than from a mechanical brush.
Makes sense. If there was dirt on the body before hand hand washing or machine washing just rubs it in.