I did AA F on the old 777-200 last year and Delta on the 747-400 from ICN-DTW two months ago. I think food and beverage wise they're about the same but Delta's IFE is way better. The Delta seat is also quite good and service was too. Here's a trip report if you want more details on Delta:
http://www.flyertalk.com/forum/trip-...n-ke-dl-j.html