Never again! I brought my dog in to use the self-service wash. First, the place is dirty. It was shortly after they opened in the morning, so it must have been still filthy from the day before. Second, the water temperature (the primary reason I brought my dog in, instead of washing her in the backyard) was all over the place. Lukewarm to really cold. The receptionist said it was because they'd been using the water all day. Third, the shampoo they supply is so watered down that you have to wash the dog 3 times to really get them clean.
Forget it. More hassle than it is worth, too expensive and cold water. And just gross. Your dog would be better off being stinky.