This is my favorite site for demo information:
It will provide statistics - but more importantly people who actually live there post extensive, hands-on info. It wll also point you to information on surrounding areas as well. Happy hunting!
As a member of FMLS you have access to demographic information. Do a search for Sandy Springs, pick a listing and select FMLS Neighborhoods. Here's an example: http://www.AtlantaRelo.com/reports/SandySprings.pdf