The worst thing about F on the 777 is that when sleeping, your head is right by the aisle with no protection, so you feel the draught from passersby, or even the odd skirt flapping over your head!
I would definitely NOT want to be in row 4 as your head is right by the galley curtain, so chatty FAs can be disturbing, and you can forget about sleeping when they start breakfast prep about 2 hours before landing.
(That's why I prefer CX J, because your head is as far from potential disturbance as possible.)
Also the video screens are small and very poor quality, so bring your own IFE.
(The video screens in J on 763 are actually much better than F on 777; not sure which screens are used in J on 777)
Happy Travels.