I just did a 6 hour flight in QR B787 in y (non-exit row). I was lucky as - probably due to my status - the middle seat stayed empty with a otherwise almost full Y. Seats are very narrow and all seats but the the middle ones have huge IFE boxes reducing foot space dramatically. I tried to upgrade at check-in but C was full. In my original booking it was A350 and later changed to B787 and I got caught this time. I would never book B787 in Y voluntarily.