I actually take the reverse view. I say ATL on the outbound because it gives you a longer flight and therefore more time to sleep on the relatively short East coast TATL.
On the way back I'd only take AF if it's the 777 with BEST seating, if it's on the A380 you'll be on an angle-flat seat. I'd tend to go with JFK on the way back to get D1 the whole way and being all DL metal you should be fine if there are any hiccups unless it's the last flight of the day.