Well, finally got to use the Skylounge (purchased via BangkokFlightServices at about $27USDpp) yesterday and figured I'd update my experience:

- purchase was a little tricky online - oddly you need to print out and sign and refax/reemail back in a creditcard invoice. Got a reply to my re-emailed in invoice within about 6hrs. I was able to simply present to the Skylounge at BKK with just my passport and didn't have to print anything out.

- lounge was kindof skimpy - minimal food offerings (a few finger sandwiches). We were the only 2 people in the entire lounge for the 1.5hrs we were there. It was about as bare as a typical RCClounge except with alcohol.

- wifi was pretty decent and no password needed; good speeds

- my biggest gripe (which unfortunately made the whole pass thing not really worth it in the end): I don't know if this was a CathayPacific thing or a BKK thing: arrived about 5hrs prior to my 4pm flight out of BKK. Cathay refused to allow us to check our bags in: they said that they were just the morning crew and that the afternoon Cathay crew would have to check us in because they were worried our bags would get lost. That meant that instead of being able to check in and avail ourselves of the lounge we had already paid for, we had to hang out until 1:30pm which is when the afternoon Cathay crew appeared at the checking counters, at which point about 50 other passengers were already lined up waiting for their counters to reopen. So it was about 2:30pm by the time we made it past security and so we had only about 1.5hrs max of lounge time. Definitely not worth it. I suspect this is a Cathay problem (probably not an issue if we had gone with ThaiAirways or someone with constant presence there) - so I would not recommend using this sort of lounge paid service if you are flying with Cathay. We only went with Cathay this round because we had Asiamiles that were about to expire - but Cathay has definitely lost me as a customer. StarAlliance all the way from now on.