Our purchase process actually started at a different CarMax location (the one on Independence Blvd.). When we could not find one we loved there, we decided to go to the location on South Blvd. The sales rep at the Independence Blvd location called ahead to a fellow rep on South Blvd and told us to ask for him there.
Frankly, this was the most painless car purchase process I've ever experienced! No hassle or anything. It took a bit to get the financing through. But once that was done, we were done with paperwork in under 30 minutes. Blew my mind!
If you're one for haggling and negotiating, this isn't your place. But if you want to avoid that, CarMax is the place to go.