I don't know why people worry so much about Atlanta. If possible avoid the rush hours. As for construction I haven't seen any on I-75 the last couple of times we went thru. Use the HOV lanes assuming you have at least two people in the vehicle.
We almost always run into a traffic slowdown somewhere, not always in the central city area either. It might take 10 minutes to get thru that but that's a lot less time than you would lose by trying to bypass the city. The ring road always seems to have worse traffic than I-75 so we just stay on 75.