I would agree: CX on a 747 is as good or better than BA on a 747. Only 12 instead of 14 seats, more space etc.
But: AMS-HKG is on a A340 as far as i remember - and they dont have the Betsy seats in all 340's. And the old F seat on the 340 is horrible.
HKG-NRT has some flights with a 747 (some stop in TPE!) with 3 classes and some other planes with only two classes.
So check: If A340 then BA, if 747 then CX.