I don't know, but what's the big hoopla about it? It is very thin, and light, but at $1,800 you are paying very dearly for a machine like that it is not that powerful.
Killer feature: extreme portablility with very good power.
And.. It is simply beautiful. It looks like a dream from a futuristic scifi movie. In fact, this may be the most beautiful computer to date - but I have to see it in person to confirm. (I still remember going crazy over the Next computer when it came out)
Weight is more important for me, though. I don't honestly need anything extremely thin.
I'm not saying I don't want one, of course.