I also just got an N9. It's incredibly smooth and snappy. Feels snappier than my old iPhone 4. It baffles me that the N9 platform, which is essentially Maemo 6, isn't being more widely adopted. Here we have a Linux based mobile OS that is capable of powering user interfaces as good and snappy as those of iOS, something even Android isn't capable of imho.
I'm doing some research on what exactly the N9 does to achieve these great results. Afaik it's not Qt, since Qt is only a cross platform wrapper and doesn't have any GUI rendering on its own. But I don't (yet) know what I'm talking about.