The LW community takes Yudkowsky seriously when he talks about quantum mechanics -- and indeed, he has cogent things to say. I think we ought to see who has something worth saying about AGI and risk.

He has found cogent things to repeat. Big difference. I knew of MWI long before I even heard of Eliezer, nothing he presents is new, and he doesn't present any actual counter arguments and ways it may be false, so he deserves -1 for that and further discounting on anything he talks about, due to one sided presentation of personal beliefs. (The biggest issue i can see is that we need QM to result in GR at large scale, and we can't figure how to do that. And so far as QM does not result in GR at large scale, it means what we know doesn't work for massive objects(as matter of physical fact), which means we don't know if there's superposition of macroscopic states, or not)

Furthermore, if I needed someone to actually do any QM, as in, e.g. for semiconductors, or making a quantum computer, or the like, he would not get hired because he doesn't really know anything from QM that is useful (and got phases wrong in his interferometer example but that's a minor point).