I've just returned from a trip involving a B787 flight and the aircraft is now on my avoid list, along with the B777 in ten across configuration due to the narrow seating. Unfortunately most airlines ruined the concept by cramming passengers in nine across when the aircraft was designed for eight.
We were lucky as the flight was very empty and I switched to a spare row and left the wife with the whole row to herself. With the middle seat empty it was okay but the seat was very narrow and a long flight with all seats occupied would have been a nightmare. It felt like a low cost narrow body.
Returning on the A350 in nine across on an almost full flight was an absolute pleasure, shoulder room was plentiful and I didn't feel boxed in at all.
I'll take the A330 in 2/4/2 over a B777 in 3/3/3 as we enjoy the couples seat next to the window with none else in the row.