Heh, that does seem weird justification, though I actually agree with ranking "Once More, With Feeling" above it. I'd have ranked "Surprise" and "Innocence" higher and dropped "The Gift" in favor of "Prophecy Girl," but in general I think their top 20 is pretty solid.
Much less agreement with the worst episodes, but the authors and I are coming from very opposed views of which season is the best. And it stands to reason, individual pet peeves are going to influence any given person's worst episode.