Analise - Preferred Service isn't really a "premium" level of service - By being a Preferred customer (which anyone can be by filling out the application), you have the benefit of having your rental info and preferences on computer file, so that when you reserve a car using your Preferred number, or Wizard number, all you do is show your driver's license at the counter and you are out of there. A preprinted rental agreement and your key should be waiting for you. You usually get lower mileage cars and should Avis run short of your type of vehicle they usually throw an upgrade your way rather than Joe Priceline. Usually even without a reservation, you can be out of the office within 90 seconds of getting to the counter. That's my experience. I rent from Avis exclusively (since my corporate rate lowers the minimum age to 21) and I find it helpful, although it kind of helps Avis more than it helps you. Preferred Select is a step up from Preferred, and supposedly gives its members a one class upgrade with every rental. I've heard this varies wildly, though. Still, as with anything else I don't have, I'd like to have it.