I fucked around in Shangrila a few times and found some decent play 3-4 times about, but most of the time I just kind of walked around and was a voyeur. (This was more recently after the loli-purge or whatever) Most of my experience with it besides that though has been people idling and basically just using the idle-room or whatever it's called to find partners for stuff in whispers.
I still love the idea of having a MUSH with a giant world to RP/ERP in, but most people seem to ignore the entire world outside the idle room as far as I've seen, granted I haven't looked super hard. I'm also a retard when it comes to MUSH shit, but I'd use the hangout command and most places would only show a max of 20ish people usually with everywhere else being 1-3.
>Penultimate MUSH is #2 in population after Shangrila (excluding furry-specific places like Tapestries), and has the aim of basically being Shangrila except being overtly friendly to sandbox play, chatting and being social, and (politely handled) niche/hardcore kinks.
I might have to look into this.