The Pugsley is an awesome looking beast but it seems that Surly now see it as something as a lightweight..check out the Surly Moonlander
A friend of mine just bought a moonlander, he have a pugsley, I think I should ask if I can by the pugsley since he won't be needing it.
I've tried it, it is so much better in the woods and on sand than a regular mtb, not as fast but i climbs far better than any bike I've ever tried.
That's one of the great things about the Pugsley and the Moonlander - they're pretty deceptive machines.
Now I'm possibly the world's worst climber, but even I can climb reasonably well on the Pugsley if the conditions are right - I think its mainly because of the immense amount of traction that you get from the comically wide tyres. Hell, mine even rolls pretty well on the road if I pump the tyres up to 35psi or so (and this is with the stock Larry/Endomorph combo). One thing you absolutely must do on a Pugsley is ride it on snow or, even better, sand - if you're not wearing a shit-eating grin by the end of it then chances are you're dead from the neck up
I haven't ridden a Moonie (yet) but if the Fatbikes UK group on Facebook is any indication there are a couple of guys on there who regularly ride up at Dalby - I'm hoping I run into them (not literally) at some point if only to say "Can I have a go on your bike, mister?"
I'm currently deciding whether or not to single-speedify mine for SSUK next year ...