Probably a 777, then. You will be amazed at how big a plane they use for the short distance to Atlanta. I wouldn't worry, then - those planes are some of the newest in their fleet, and on those runs they usually have good service. Boarding and deplaning take a long time, though, so if you are making a connection you want to look in the back of the inflight magazine for where your next gate is, in case it is half way across the airport.