I'll use a touchless wash to knock of the heavy stuff before I use the hose at home. Be careful with some of the high pressure washes around seals and brakes. If you're talking public wash as in guys washing and drying, though, I'd stay far away. The best way to get micro scratches and swirl marks is to have someone use a towel on the car. Who knows what they've used it for before or how they've taken care of it. My recommendation is to always use a microfiber towel to blot the car dry, not wipe it dry.