The 787 Y seats will be similar to the 77W and 77D 3-4-3 layout in terms of IFE and seat width. If you can get MCE on one of those planes the extra space is probably worth it.
Otherwise, if you're going to be crammed into the narrow seat anyways, I'd take the 787 for higher humidity and pressurization. I have noticed a difference with those on prior 787 longhaul flights.