As a follow up....I decided to try CarMax for a surplus vehicle that the Mrs. wanted out of our driveway. It was a decent experience. They matched their online offer exactly. I'm sure we would have made more from a private sale (or less from a dealer trade in) but it was quick and saved me the hassle of listing and sorting through real/fake offers. It was for a 13 year old car with 123k on the odometer in less than perfect condition, so the potential gain from a private sale would have been minimal anyway.