travelsforfun, I agree with what you say bar one sentence: “To be fair, how much difference there is between the lounges available to Emerald and Sapphire tier members varies substantially from carrier to carrier.” In fact, I think you may have meant to say that the difference between the lounges varies from airport (terminal) to airport (terminal), given that under the oneworld system, whether one qualifies for lounge access by virtue of travel class or status, one can use a lounge operated by any oneworld carrier (of the appropriate class, of course) – although this doesn’t always seem to be understood by many of the passengers. Thus, a business class AA passenger flying out of LHR can use any of the J lounges offered by AA, CX or BA – of course their invitation says the AA lounge, but there is nothing to stop them using either of the others – and yet most of them end up in the AA lounge, which is pretty miserable (IMHO).
Similarly, as I have mentioned on here before, when I fly out of LHR – usually on CX or AY – I tend to use the BA F lounge (as an emerald) even though my invitation specifies the CX lounge. When I have flown out of HKG on BA or AY, I use the CX F lounges, although my invitations specify the QF lounge (if on BA) or the Premium Plaza lounge (if on AY). Of course in some airports the terminal factors in as well – for example, in some US airports it is relatively easy to get from a lounge in one terminal to a departure gate in another, whereas in other airports it is impossible or impractical.
Martyn, I was specifically looking at frequent flyer benefits under alliance systems rather than mileage rewards (which are more airline-based, despite the ability to earn and burn across alliances), although your point is well taken. I haven’t tried the new CX lounge in BKK yet – so please do send in a report! Mind you, you should come to HK and try the new CX F lounge at The Pier. It isn’t huge, but it is delightfully quiet compared to many of the other lounges, the dining is superb, and it has a truly luxurious feel. The only downside of it compared to The Wing F (IMHO) is at breakfast, since there is no buffet so all food has to be ordered and it can be a bit slow. Also, the ambience of the restaurant doesn’t quite seem to work in daylight – but in the evening it is gorgeous. Well worth schlepping all the way up to the far end of the terminal building even if you are flying BA!