JohnPhelanAustralia makes a very good point about the A380, notoriously bad punctuality. I could not agree that the QF product in First on the 747 is pleasant however. It is a barn and there is absolutely nothing about the interior that is welcoming or luxurious. Indeed row 2 is a nightmare due to the awful layout of the cabin. 4 rows with 2 in the middle. 4A and 4K have bassinet positions. It is simply awful. Service is generally good but crew, as I stated before, are (IMHO) overly familiar.
The option of using a combination of BA CX over HKG makes a lot of sense but on balance CX out performs them all. There are just 9 seats in F on a 747.