Who's been to a sex party?

It's always something that's interested me, both gay (like GoldenBoysUSA NYC) and straight/kink (Sanctum/SNCTM) but never really seen much feedback about them besides some old blog posts. Is it one of those "to good to be true" deals? I'm guessing the screening process may make the biggest difference, with stricter parties (like GBU) being more enjoyable since everyone knows what to expect. NYC and LA seem to be the main locations for these unsurprisingly.

So what's your sex party story/experience?