Gwern, Hal Finny, Wei Dai, Hannu Rajaniemi, Aaron Swartz, and Scott Alexander are some of the more well-known (outside of LessWrong) former members. It really was an interesting community for a while. There were meet-ups and Yudkowsky did solicit for his nonprofit, but it never seemed culty to me. And none of the people I mentioned ever seemed wary of criticizing Yudkowsky when they thought he was wrong. See, for example, Gwern's epic reply to Yudkowsky's post on automation: http://lesswrong.com/lw/hh4/the_robots_ai_and_unemployment_a...
This doesn't seem like the type of reply an entranced follower would give their guru. The fact that this very-critical comment got twice as many upvotes as the original post is telling of the attitude of the community as a whole.