For $450, its definitely worth to sample the hard product and given the horrible Y on the 777, a good way to spend some $s for a 6 hour odd flight in J. Don't get your hopes too high and you should be fine. Its a night flight so there isn't too much that you can do, but I would expect better levels of service given that most pax would be sleeping. And, the JFK lounge is great and you can have drinks + dinner there - note that it is open all day so if you have some time to kill, come a bit early and enjoy the views of the tarmac.