I assume you mean CX
= Cathay Pacific not CW
= Air Marshall Island. If the latter really flew between LHR
, it would be the airline to choose ...
All three airlines know how to fly a First Class passenger in style.
I assume you even could fly BA
outbound and CX
on the return (or vice versa) on one ticket, if you want to sample both products.
like you say has the charm of operating the A380 with its luxurious First Class. The trip is longer, but the stopover can be seen as a positive or negative thing.
When flying in Eco, it is a welcomed opportunity to stretch your legs (and arms).
When flying in First, I would see that stop as an interruption of my attempt to sleep all the way on the flight from HKG
Therefore I would prefer the nonstop service between the two cities - and then would go for CX
-metal (and hospitality), if timings are suitable.
Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !