Hello!
There are some major differences in business class between the 762 and the763. I'll start with the 762. You will not have the new business class. You will have the media player and enhanced meal service however. The new business class is only available on four of the five 763's. There are only 12 seats on the 762 in a 2-2-2 configuration. I would suggest row one seats on the left because you are not affected by light and noise from economy and the forward galley. The 763 serving JFK does usually have the new business class. Seating is 2-2-2 in three rows. I prefer row 2 on the left hand side because you get your first meal choice and you are not bothered by the forward galley or economy class.

The Bottom Line:
If you want the new business class choose the 763!

Hope this helps.
-LOTPolish