I do this one occasionally, its tolerable, they do regular drinks services and bring water round quite often, no entertainment so I take my Archos video player.
Leg room is on the snug side in Economy for me six foot ish, but by no means as unusually cruel as the Monarch A321 I came back from Turkey on yesterday, purgatorial.
ATL is not much fun it has to be said, takes an hour or so to pass through I find, there is a traine ride to the terminal, then another to the Car Rental Centre which is a pretty good facility, rented a nice new Camaro which was fun (work were paying).
Did Business Class courtesy of a family freind who use to be a high up at MAN, was on the old Tri-Stars, that was nice, the Plane and the Stewardesses were right from 1978 ! but brilliant.