Atlanta is sufficiently cosmopolitan and citylike, yet considerably cheaper than almost any other metro area in the US with a significant technology sector. This means you get both (comparative) affordability and the benefits of being in an IT-savvy city. Sure, it's pretty ass-backward compared to, say, the Valley or NYC, but it's highly functional as an urban technology space. Don't underestimate it.

That alone can be a huge advantage to a startup, especially those going the bootstrap route who are not nearly as dependent on the systemic VC ecosystem but highly dependent on being close to other technology companies and/or corporate customers.

It's also a major telecom hub. That's why I stay here.