The manual focus "clutch" mechanism is similar to the one on the Olympus 12mm and new 17mm. The advantage is that it introduces hard stops at each end of the focus scale and makes the lens feel like a true manual focus lens instead if a focus by wire lens (although it technically still is). It also allows the lens to have useful distance and DOF scales on the barrell of the lens, which makes it easy to set up for zone focus and hyperfocal shooting. This last poin is less critical on the X-series cams than on m43 cams because Fuji already has very useable electronic distance scales in the various viewing options (even the OVF). But the Olympus 12mm is already a pleasure to work with for this clutch mechanism and I'm sure the new Fuji and new Olympus will be too.
One thing I wish the Fuji Guys had shown was the view through the X-Pro's OVF with the 14 - I'd really like to see where the framelines line up.
-Ray