Confirming what others have said. BA LHR T5 has THE best arrival lounges - full English/continental breakfast, masses of space, newspapers, Elemis spa and products, waiter service and separate room for F passengers (who also get cabanas with infinity baths) BUT, although there are loads of them so it is rare to queue, the showers are woeful. CX HKG arrival lounge has great showers but too few of them - last time I went there, I queued for an hour and then gave up and went home (original plan was to shower and change and go straight to the office) and the food offering is AWFUL - truly dreadful. AA arrival lounge at LHR (used by CX for certain flights) is in the middle - nothing stellar, nothing awful. Enough space for the traffic they get, decent showers (towels could be better, but quite acceptable), pressing service which works surprisingly well, and enough in the way of a decent hot/continental breakfast offering to satisfy without being overly special.

I would use BA and AA Arrival lounges in LHR every time UNLESS I was time-constrained. CX HKG arrival I would use ONLY if I was time-constrained.

Given the effort CX make with their other lounges (except G16, which is awful), The Arrival is (or should be) quite an embarrassment