Eastlake YMCA is a great gym. Joi has one of the best classes. She challenges you to reach the next level and does a lot of core exercises which help improve stability, balance and posture. I highly recommend you take her classes and do what you are capable of doing. Since doing her class I am stronger physically and I am more flexible.
I'm not a gym rat. I'd rather spend my money on over-priced trendy fitness classes or just go for a run outside! But the Y is a program I can get behind. I've been to several Y's around Atlanta (and even Nashville) and they're all really nice. Like REALLY nice! Their prices are super reasonable, especially for family memberships. Plus they come with free classes, they usually have pools, and they actually do some good in the community.