My wife and I flew JAL65 last week SAN-NRT and I can only say good things about it. Last intercontinental flight was Y on DL to CDG so I don't know that I was able to tell the difference between cabin altitude on 787 vs. flat out being in a better seat with better service but it was a great flight. We had the Japanese fare and the seat is lie-flat albeit on an incline. Came home in F NRT-DFW and the plane was in rough shape (though crew were friendly enough). With the 787's being brand new in addition to being parked for 4 months, they're in really good shape right now.
PM me if you want more specifics but I would say JAL is a pleasant way to go (at least by American standards, not sure they can match Asiana or Cathay from what I've read on here but I didn't have experience with them so no pain there).