As far as having meet n greets, I'd propose somewhere in Midtown. Thats where Tech is, its where Technology Square is, its where all the growth is. The Perimeter area is just full of old established insurance companies, marketing and spamming companies -- the "old school" suits. Midtown is where all the young professionals and visionaries are, plus its literally the only place centralized to all of the metro atlanta area instead of just the northern edge like Perimeter would be.
Just my two cents ;)