My personal situation is semi-closed; we have an interesting situation based on mutual freedom and open discussion about what each member wishes to do — we’re also non-hierarchical to a large degree, but respectful at the same time. Personally, I couldn’t do an unrestricted open relationship, but that’s my personal preference. I’ll also say as a footnote to almost all of my work on poly, a lot of the problems you’re speaking of like “unicorn chasers” and things of the like could be largely avoided by avoiding the polyamorous culture you also speak of. I’m sure good people exist in the culture, to be certain, but I’ve personally never met a single one, and have generally preferred that my love not be a “lifestyle,” but again, this is a personal choice of mine, and people should do whatever works for them and makes them and those around them happy. As a rule of thumb, I’ve learned that whenever people find paradise, other people will come along and try to pollute that as much as possible, and the poly community is no exception.
I also will say that we have a massive problem with people who are swingers identifying as “polyamory” when they’re anything but trying to hold multiple concurrent relationships, they’re just trying to add a complimentary piece to an existing relationship on unequal terms and on their terms, which arguably isn’t polyamory. It’s definitely not the same thing as my experience that I live every single day.