Nothing at all against SIAI but
A couple of times I asked SIAI about the idea of splitting my donations with some other group, and of course they said that donating all of the money to them would still be the most leveraged way for me to reduce existential risks.
If you're in doubt and seeking expert advice you should pick an expert that lacks really obvious institutional incentives to give one answer over others.
Regarding the rest of the comment I found it kind of weird and something freaked me out about it, though I'm not sure quite what. That doesn't mean you're doing anything wrong, I might just have biases or assumptions that make what you're doing seem weird to me. I think it has something to do with your lack of skepticism or cynicism and the focus on looking for someone to follow that MatthewB mentioned. I guess your comment pattern matches with things a very religious person would say: I'm just not sure if that means you're doing something wrong or if I'm having an adverse reaction to a reasonable set of behaviors because I have irrationally averse reactions to things that look religious.
Yeah, I realized that it was silly for me to ask SIAI what they thought about the idea of giving SIAI less money, but I didn't know who else to ask, and I still didn't have enough confidence in my own sanity to try to make this decision on my own. And I was kinda hoping that the people at SIAI were rational enough to give an accurate and reasonably unbiased answer, despite the institutional incentives. SIAI has a very real and very important mission, and I would have hoped that its members would be able to rationally think about what is best for the miss...
It has been claimed on this site that the fundamental question of rationality is "What do you believe, and why do you believe it?".
A good question it is, but I claim there is another of equal importance. I ask you, Less Wrong...
What are you doing?
And why are you doing it?