Personally, when we were changing gyms I did not consider GAA. GAA places really, really well. They are a strong gym. But I have a number of friends who currently have their kids there and others who did have their kids there and left. From talking to all of them I did not want my girls there.
If you are just looking for a gym with a girls team then there are a lot of options in the metro area; but I don't know for Buckhead specifically.
I have seen GA Elite (the Athens gym) at competitions and they really do seem amazing; but it is way more of a drive than I would ever consider.
In the north/west metro area with optionals teams are Cobb Challengers (not many on their girls optionals team), North Metro Gymnastics Center (in Woodstock), Ga Allstars, Ultimate in Duluth, Roswell (already mentioned), All Around in Alpharetta... There are just a ton of teams.