My impression is that Hacker News is above average, but still a noticeable notch below LW. Same goes for sites like the Richard Dawkins and JREF forums (perhaps two notches in those cases), and the comments sections of blogs of various academics (such as Overcoming Bias).
The key thing here separating Hacker News from LW is the "variety of topics". While HN is officially centered around startup culture (which like cata, I have no particular interest in), the community is happy to link to and discuss just about anything of intellectual interest. Today there's a link about punctuation marks for indicating irony.
The level of discourse might not be quite up to LW, but the subject matter is a lot more inclusive.