The 787-9 seats are not great compared to the legacy seats.. the only thing they have going for them are the reverse herringbone setup. Other then that; They are narrow, feel cheap, the seatbelt with the security inflator takes away from seat width when not buckled, the seats are quite often broken in some way, the legrest is sub-par (compared to the 2-2-2 diamond seats), the buttons are constantly pressed when you rest an arm or try to look outside, the screen is uncomfortably close..
I haven't flown the 787-10 yet with the Jamco seats. So I wonder if those are an improvement.