You'll find Flagship P to be a major improvement over domestic F flights. Dinner service includes caviar & salmon, salad with chicken & lobster, more entree choices, and ice cream sundaes.
Seats should also be much better, though I'd suggest trying for a 763 to get the new seats; you won't find them on the 762s.
If I were to rank premium service in order of value, I'd go Flagship P, Flagship J, Domestic F.