ATL's easy to get around. Like people have said above, you're most likely to depart out of A or B, but T, C, D or E are all possibilities for arriving or departing. There are several resturants & shops in each concourse in the area around the tram stops & fast food further into the terminals (if you have time).
I like ATL- it's a nice airport & always seems to be clean. As for the trams, they run every two minutes or so, but they can get crowded & you could be jammed in like sardines- I've had that happen to me before.
A310/319/320/321/333, ARJ, BN2, B722/73S/733/734/735/73G/738/739/744/757/753/767/763/764/777, CR1/2/7/9, DH6, 328, EM2/ERJ/E70/E75/E90, F28/100, J31, L10/12/15, DC9/D93/D94/D95/M80/M88/M90/D10, SF3, SST