Most listings are in the $20's per square foot per year. The McDonough submarket is going through a a boost in rates. In the last 3 months, the median rate rose $24 per sqft per year.
Compared to the rest of the Metro Atlanta market, the McDonough region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 2 listings have been made available, which means spaces most likley are going fast. You'll want to be prepared to make an offer immediately. About 350% of the listings in the McDonough are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 650 sqft. Most buildings in this market are approximately 1 stories. Most buildings in this region were built in 2006 and are Class B.