I think EY class on at least some of the KE 777's serving SFO don't have AVOD, if memory serves me right. I don't know about IAD so I recommend checking. Personally if I was sitting in EY I would probably base my decision solely on stopovers/travel time, seat comfort and the IFE status, because it seems a little crazy to me to be getting worked up over the in-flight meals on EY, no matter what carrier or cuisine. CX you're guaranteed to have AVOD on your long-haul segment, whereas I don't know what plane KE will serve you to IAD.