I feel the same way. I have the N9 since February and the N900 since fall 2010.

N9 is a phenomenal device, both in design and UI.

But the N900 has that "something". That "something" you can't easily describe in words. It is the most joyfull device to use imo.
In 2012, it still delivers.

I will use a Sega Dreamcast slogan: "It's thinking!"