I worked as a valet for a few months in college during the summertime. I drove many nice cars. Unfortunately the great cars get to park up front. Lambo's, Ferrari's, etc. But the owners usually just throw a $20 or more for the tip. I got to drive them a whole 20 feet or so. Nothing like having the car stalling in front of the customer, but they are not easy to drive without experience. The clutches are super stiff and not easy to get it right on the first shot without riding the clutch. We had a few people scratch and dent a few cars. They were fired and the owners were not happy. Who would be?
I personally I do not Valet. If anything I tell them I will park it myself and will still pay. They usually get it, but have had times where there was almost a huge argument. Ask for the manager and pay $20 to park up front if you absolutely have to Valet.