I never said ATL-ORD is a "good commute." That's a bit of an oxymoron. I just want you to know my experiences on this commute so far. I too heard the horror stories and maybe it is much worse at different times of the year. I also have only used Delta a couple times for the exact reasons that others mentioned in this thread regarding passenger reroutes and such. My main point is if your options are ATL-ORD or ATL-IAD, go with ATL-ORD. At least you have more options for your commuter clause.
Commuting sucks any way you slice it. Good luck to you and hope it works out for you.