I must say it is really an innovative and a usable UI concept. It seems that Jolla has all those MeeGo engineers from Nokia who developed the Swipe UI of N9.
The pulley menu is a great conept. You slide the menu to make the selection. Nice touch.
Another useful feature is the stuff you can operate on the "multitasked windows". I wonder though, how would the UI display more than 4 multitasked windows - displaying smaller icons or may be provide a horizontal navigation for 4+ windows.
Definitely an OS worth waiting for. It would be awesome if I can deploy it on my N9!