I'm planning to check out both GADPA and IDPA this week some time. Will watch the first time and then get clip belts and proper gears. After doing some research, I am leaning more toward GADPA. SharpShooter USA on Mondays is where I am leaning. I live in North Alpharetta/Cumming/Johns Creek area.
Just found a Johns Creek Indoor Gun Range one on Thursday so I will be checking that out tomorrow evening.
http://www.gadpa.com/JohnsCreek