I guess the dedicated rooms to be specific. Only been to one house and didn't like the vibe. I prefer not to mingle with many others beyond who I have come to see. Plus there's enough stories about houses in general (upselling, etc.) and the one time I was there I experienced exactly that. I'm happy to pay fairly, but I don't like that tactic at all.

Dommes who have a dedicated, room with quality (sturdy) equipment are what I have found most to my liking. The authenticity is important. You can tell cheapness right away. Smaller and intimate is my preference. Just enough room necessary to do whatever activity you're doing. I also think private dungeons tend to be cleaner from what I've experienced.