Eliezer Yudkowsky is quite smart with some deep understandings of the world (along with some less good ideas), as best I can tell. I've definitely learned interesting things or been sent down interesting paths from articles of his that I've read.

However, he would be served very well to work on eliminating the moderate pomposity that permeates much of his writing. He is also overly verbose sometimes. Fixing those two issues would reduce a lot of the beef he gets, I think.