Downloaded the video - it looks cool!
ZBrush is $500, and Mudbox is $700 - but from what I can tell so far (need to get my hands on a trial version of ZBrush to make sure!) I'd like the process of manipulation better in Mudbox (MB).

The only downside to Mudbox from what I can tell is that it seems better to start with an at least basic form to import into MB (like a figure from Poser) for finessing and detailing. This isn't that much of a problem for me as I have Poser an C4D - but in ZB you can start from absolute scratch, and it's a couple hundred bucks cheaper...

Pro/con/pro/con/pro/con... ;-)