Just installed the newest version to my N9 and from 30 minutes of playing around I can say that it's pretty smooth indeed. I'm probably gonna use this now as my main OS for my N9. Sure the experience is far from perfect and I have the same issues as mikecomputing, but I didn't use my N9 for much else than phone, sms, mail and occasional web browsing which seems to work just fine. I hope we get the store working at somepoint

The browser seemed fine by me. I just tried facebook touch but that seemed to work as smooth as you would expect from the N9. UX is smooth, some gliching here and there but it's not a big deal.