Qatar's 787 was pretty uncomfortable for me on a 6 hour flight. 9 across seating and a very tight seat pitch (31 inch) is not ideal for that long a flight. The QR 777 I took had slightly wider seats (still 9 across) and a little more leg room but much more noise in the cabin compared with a 787 or A380.

I've only flown Emirates A380, but for me it beats both easily in terms of comfort.