The obvious answer is TORTURE, all else equal, and I'm pretty sure this is obvious to Eliezer too.

That is the straightforward utilitarian answer, without any question. However, it is not the common intuition, and even if Eliezer agrees with you he is evidently aware that the common intuition disagrees, because otherwise he would not bother blogging it. It's the contradiction between intuition and philosophical conclusion that makes it an interesting topic.