I, too, would love to hear some side-by-side comparisons. Part of me thinks that if fat is good, fatter must be better, but another part of me thinks that the Pugsley might be more versatile over all because it seems like there are only a handful of conditions under which an increasingly fatter tire would provide an increasingly better ride (and even then only up to a point). I would think that sand would be one of those cases. But even then I would think the question might be: Are you going to ride primarily on sand, frequently on sand, or occasionally on sand?
That said, I would guess that you'd be more fat tire experience in the mountain biking section. And since the Moonlander only just hit the market, it might be a while before we hear any significant amount of feedback on it.