My husband bought a car off ebay and has been thrilled with it. He had looked around near home for a '69 Chevy Impala and had no luck. He found one on ebay and the bidding started. I believe he paid $4000 for it, rounded up his best friend, and off to New York they went. He is a mechanic so he checked it out when he got there, gave it his own seal of approval, and drove it home to North Carolina. We have had no problems with it and it has only required basic maintenance. If the right situation arose, we would gladly buy another vehicle off ebay.
I must note that my husband had frequent contact with the seller and asked many, many questions. The seller was very upfront and honest about the car, happily volunteering information about where the car had been and how it had been treated since he had bought it. As far as I know, the seller still emails my husband periodically to see if he still enjoys the car. The car was bought over a year ago.