We just came back I-75 from ATL the week of Oct 5th.
We didn't have any construction problems at all. There is a bit near Macon but we went through on Sunday and no signs of delays anywhere. There is also a bit near Valdosta, but the last three times through there, no delays.
We did encounter some on the way home at the Macon construction but it was a delay on the southbound, and lucky for us we were going Northbound.
Therefore, no problems or delays for us the first week of October.
I would check the posted website from pooh_mania and definately stick to I-75 as it will be faster, despite any delays you may encounter.
Also, another hint - don't take the I-285 bi-pass around the city of ATL as AAA will always route you through. At busy times, trucks are not allowed on I-75 through the city, and the HOV (commuter lanes) on I-75 are great! All you need is one other passenger in the car to qualify to drive in the HOV. I have found (we live north of ATL) that a great number of accidents seem to happen on the bi-pass (I-285) and they seem to have the greatest proportion of delays, and much greater volume of traffic. This stands to reason because there are so many commuters to the suburbs here. I can't say that driving straight through ATL has ever been a problem for us.
Therefore, drive straight through the city on I-75 as well, and use the HOV lane.