Even though this thread is a bit long in the tooth, it's the most appropriate for my question. And an update to this discussion is probably worthwhile. I started with wondering which J seat to pick on the B777, but now I'm wondering if opting for the B763 is a better idea.

I currently have a J MileSAAver award DCA-JFK-EZE on a B777. There are currently seats available via DFW on the B763 and MIA on the B777. I'm debating whether to change to a MIA or DFW flight. My lines of thought:

1) JFK is a longer flight affording me the opportunity to get more sleep and be able to hit the ground running at EZE. So MIA the option less desireable. I think the DFW flight is about the same duration.
2) This thread states B763 food/service is better than B777 (both for J). Is this still true? I did a B763 J flight this past August and thought the food was very good. But I'm not so sure this matters with an overnight flight.
3) MIA arrives 6:10AM. DFW arrives 8:15AM. JFK arrives 9:50AM. I lose nearly 4 hours on the ground at EZE, that would likely be used to sleep. The other drawback to the JFK flight is it appears to be late with regularity.

On either plane I plan to go with a starboard-side aisle seat.

Comments?