I like Comprehensive Pet Therapy (www.cpt-training.com). It's $150 for 8 weeks and if you go to the Sandy Springs location, it's indoors. They limit the class to 12 so you get the social interaction, but not overly distracting like in Petsmart. From East Cobb, it takes about 20 minutes to get there going up Johnson Ferry. They also have a 2-week puppy class that's good just to get your dog comfortable around other dogs in a somewhat controlled setting.
I am at Petsmart in puppy class now. When we took the boys to obedience class we used Susie Aga (Atlanta Dog Trainer). She was having a group class at the vet we used at the time. I really liked her training style, but could not remember her name when it was time to sign Harlow up for class (it has been over 7 years since we took the boys). We will more than likely go back to Susie for our advanced training classes.