I rarely fly United over the Pacific. Usually prefer EVA, Singapore Airlines, Air Canada or Asiana.
This time I flew Economy on United from HK to SF. The plane was completely full, so even with my Star Alliance Gold status I had to settle for a middle seat in a row of 4.
Notwithstanding this little inconvenience I thought this flight went very well. Flight attendants were professional, food was plentiful, plane (a B777-300) was clean and seats comfortable. The audio system had enough content to carry us through another 6 hours...
The only suggestion for United: make space for a Premium Economy class. Many Asian airlines offer this class over the Pacific and it becoming increasingly popular.