You should check greatschools.net and compare CRCT scores and whatever other criteria are important to you.
I think that the lifestyle choice of Suwannee vs. east Cobb is pretty radical, but it all depends on business and personal commuting, family proximity, and whatever else is important to you.
Greatschools.net is the go to site for this and I'm using their Iphone app frequently nowadays.
From there, go to the school system websites and schedule some meetings and tours.
If any agent steps up here and makes a claim that one area is better than the other, then beware, they speak with forked tongue...