Hardware = Of course. You don't have to be a genius to figure that one out. N9 hardware is already outdated even before release.

UI useability = We'll have to see. But as an owner of nearly every mobile OS devices, I would say N9 is ahead of every OS right now for its simplicity, effectiveness and speed. (obviously, it does have some weak points. Hopefully that's ironed out by PR1.1...)

btw, I love this video showing how fast you can use the N9:
http://www.youtube.com/watch?v=9d5eRu_bMFo