I've been to Isis Quest before the name and location change with the ex-misses over 20 times.
From my experience I would say the following.
1, If your a single bloke wanting a shag pay for an escort it will work out cheaper, unless you look like Tom Hardy then your in with a 50/50 chance. Friday and Saturday nights were always full off single blokes nursing a semi on the chance they might get some action, most couples are happy for you to watch and wank and thats it.
2, It was a bit clickly, so unless you had been there over a dozen times and people started to reconise you as a regular you got nowhere. Even more so for single lads.
3, A few couples tend to be up there own arse, about there own self importance and how attractive they are, and only go there so they can say they are swingers. But equaly just as many couples go there to enjoy the liberated atmosphere.
4, Themed nights tend to be very hit and miss, so unless you know people are turning up there could only be you and the staff and a single bloke nursing a semi.
So for the best results, go there regular with a misses that is game for most stuff and you will figure out what works best the pair of you. If you single, you just join the pack of 10 single blokes nurseing a semi hoping for there lucky day.