I have heard both good and bad things about CF BTB - they may be a little short on the Oly lifts coaching side.
Crossfit Decatur is awesome. Super expensive, but awesome. Crossfit Atlanta and Crossfit North Atlanta are probably the best, but may a bit further from you.
I've got a garage gym right around the corner from Emory where I have been training people. I've got my level 1 certification and am building a cool little community. Of course, we'd love to have an out of towner!
If you're experienced, I'd suggest shooting an email to the owners and ask if you can come check it out. They will probably let you, and you can figure out where you fit the best.
four-oh-four, seven-two-3, one-five-seven-seven