Usually, when I see a carwash with a self-pay machine, I don't bother to stop. I once had a traumatizing experience with a suburban carwash where I inserted a $20 bill and it literally shot 20 dollars worth of quarters at me than all the teenagers around me started honking. It gave me little faith in car washes.
But, my car was so dirty from city driving, that I just had it and needed a car wash. To my happiness, the pay machine didn't fail me. I went right in for the $15 wash after paying and being waived in by the attendant. Not sure if this is standard, but the wash had tons of colorful lights inside. The wash itself was fast and powerful. Also, even though I didn't have a hand-towel dry, the nicest gal waved me out with a big smile and told me to have a nice day. It was just really sweet.
So, what can someone really say about a car wash? My car is clean and I'm happy!