I like Park and Ticket with a coupon for 2 days free. Coupons are available on the website.
http://www.parknticket.com/index.htm
It is at the first light on Camp Creek parkway, and has constant shuttles.
It is worth it to be in my own car under my own control in a safe enviroment shortly after I leave the airport. They are efficient but sometimes full during mid week if you start your trip on a Tuesday or Wednesday.
I used to live near the Brookhaven MARTA station and used the secured parking. Sometimes I found they are full when I pulled in to use them and I was out of luck. Once or twice I got by parking in the free area but risk getting towed.