Its Air China
.....
ide pass and take United C over AC F - and Have!
If you dont care about entertainment, food quality or timetable reliability AND you love a hot cabin with cabin crew who dont speak english take the chinese copy of Swiss First.
If you want to get where you are going and sleep well and eat fine, but dont mind upgradees and surly service (on occasion) UA F is the way to go.
frankly i dont see much difference between UA C and F except F is more private when traveling alone