I depends on where in Atlanta you want to bicycle. I commute from Stone Mountain (east side of Atlanta) to downtown Atlanta. I enjoy it, but there are many who would think my route is not for them, since there is almost no bicycle-specific road design. I just got a map and created my own routes.

Atlanta and surrounding towns are not paved grid-like. You really have to map out your routes and explore them in your spare time.

One thing you'll almost never get around here: snow. I don't know if that's good or bad in your opinion, but that's the way it is. I don't think summers are really any hotter than, say, Washington DC, for example, and suprisingly, they can be slightly less humid. Summers are just longer and winters are shorter and milder.