We drove about a 1200 mile round trip down to ALT just to go to the GA right after christmas last year. Personally I loved it, I thought the reef was my favorite, I just sat on the benches staring for ever. The longer you look the more you will see, very cool. I agree you really need to go when it's slow and not alot of people are around. One the way home we stopped at the Aquarium resturant in the Nashville Mall. Wholy Crap! that place is amazing! I think it was 200K gallons with no coral, but black tip sharks, 8 foot long wolf eels, schools of naso and achilles tangs, we loved the GA, but the Aquarium resturant really blew us away. I often thought of moving to Nashville, nothing like that in our Malls.
Anyway if you care at all about saltwater fish, you need to make the trip to ATL.