I went to one once out of intense curiosity. My account of it is one one of the threads here. Anyway, it really wasn’t sleazy at all. Everyone was very nice and respectful, for one. No creeps. It was someone’s house, which was clean and well-decorated, with the added bonus of having a hot tub and a whole bunch of equipment and rooms downstairs for play.
Everyone stripped down and mingled. It was “pan-sexual”, so there were interesting combinations of people playing with each other, but it was also okay to just watch (respectfully) if you didn’t want to participate. Bowls of condoms, latex gloves, and lube scattered around. There were some semi-private rooms/spaces, but it was mostly open. There were some mattresses on the floor in some areas, a padded table, a sex sling, and a BDSM room with a cage, a rack, and I can’t remember what else.
I got quite the sex education that night.. saw things I’d only read about. :P