Cline,
When my wife's 2005 V70R was 11 months old, and we wanted to get out of it (due to so many problems with it), I took it to Carmax for their trade-in evaluation. The car had 16k miles, was essentially brand new inside and out, and had 2k mile old PS2s. No dents or scratches, garaged since new, essentially perfect. It listed for about $46k.
Their offer was $25k. I literally laughed in this guy's face. He tried to convince me of all "the work" he had done researching the car's price, called other stores, district manager, etc, since it was such a rare car, etc. Perhaps a 6spd manual in such a car freaked them out.
I said thanks, no thanks. Retail it could have probably sold in the mid-30's at the time. I called a friend up in PA who has been buying cars at Manheim auction there for many years. He said he could easily get $29k minimum for it if I sent it to him.
I put an ad up in a Volvo forum saying I was selling the car wholesale at $30k firm. Within two hours I had a reply from a dealer in Rock Hill who was worried he was too late to get it. Sold...in two hours for $5k more than Carmax's "great deal" offer.
FWIW, that was my only experience with them. I think they price cars well below what I'd call real wholesale value -- at least they did with mine.