I have used USAA's service, it actually saved be money. I was looking for a Hybrid Camry base with just a couple of additions worth $750 retail. I wanted to pay a certain amount. I took printout and went to two dealers, they laughed at me and shooed me away. I called the third dealer, primarily to avoid the embarrassment and told the guy exactly what I was looking for and how much I wanted to pay. He willingly agreed, even gave me a $1000 more for my tradin than the other two guys. What I found out though was that I didn't actually call and deal with the main dealer but it was their online dept., located about 1/2 mile away. So in my case I did get a discount. It was in the month of March, later during model year clearance and year end clearance, I could have gotten at the same price or maybe even less.... so i guess the car buying services' prices are better during the regular months but same or higher during the crazy sale seasons...