Well, I do all of my long-haul flying on AA. My personal choice, given the length of my trips, is the 763. I am never in F, but always find a way to get a J seat on these flights, most of which are to somewhere in Western Europe. I find the service the best on this aircraft in business class, when compared to the other AA planes. Also, unlike the 777, there is no middle seat anywhere in business. And, despite its somewhat awkward nature, I like the DVD player a lot more than the 777 IFE.
Also, when one is in Y, the 763 is the only AA plane that will not require anyone to be more than two seats deep. The A300 does this as well, but there are far fewer good seats, the Y seats are older, and two people will have to be two deep in the middle section (as that plane is 2x4x2), unlike only one person has to be in the middle on the 763 (2x3x2).