I had a 2 hour test ride on one the other day. In short - brilliant.
It started out in the wet, but me being lazy I didn't want to put my waterproofs on, so just rode in leathers. This fairing is amazing - how it kept the rain off I don't know, but it just seems to work. The mirriors even seemed to keep my hands dry, which I really don't get as they're below by a good few inches!!
I rode town, A and B roads and a little bit on the motorway too. In a strong, gusting crosswind it was stable and predictable. It pulled well in high gears, and was easily the most comfortable bike I've ever ridden.
As soon as car is sold, I'll be putting a deposit down and getting one. Surely the highest praise I can offer!