CarMax has a very nice selection. However, the experience I had was so frustrating. The car I wanted was in Louisville, KY, so I paid to have it shipped to Memphis. I waited over 2 weeks and still no car. Come to find out, they sold it in Louisville and never bothered to tell me. It took over a month to get my money refunded. Then, they were unable to find another car of the same model for the same price. They were quick to offer me a car that was $2000 more expensive. No thanks!
Beware of CarMax, especially if you are having a car transferred from another location!
PROS: large selection
CONS: awful customer service