I could do a lot of talking and rehashing of other people's reviews, but I'm just going to point you to Engadget's review. Not only is the N9 by far the best looking phone on the market today - nothing comes even close, and yes, I'm stating that as a fact - MeeGo itself is actually incredibly interesting. It has its own unique user interface paradigm, and as far as smoothness and responsiveness go, it's right up there with Windows Phone 7 (which I find one notch above iOS, and two notches above Android).
Just watch Engadget's half hour video tour of the stillborn operating system. It's magical.
I haven't ever touched an N9 (if any of you work at Nokia, this is a massive, glowing, and shimmering hint), but from Engadget's and others' reviews of the N9 (which will only be available in a limited number of markets), it becomes clear that this phone is Nokia's swan song. The last phone built and designed entirely in Keilaniemi in an end-to-end fashion, both hardware and software.
The N9 is the ultimate culmination of Nokia's 140+ year history, starting with a pulp mill in Tampere, and ending with one of the most successful and most influential technology companies in the world. You think Android or iOS made an impact on this world? Don't make me laugh - those guys are barely fit to bring in Nokia's slippers in the morning. Nokia not only invented the mobile phone (together with Motorola), they pretty much invented the entire back-end which supports it to this very day. Nokia made the mobile phone available to everyone - not just rich kids in the west - and thereby changed the entire world for the better.
In the history books of the future, Android and iOS will barely be footnotes. End rant.
The N9, brought to market before Nokia's Windows Phone 7 handsets, is proof that Elop was lying. Nokia did have more options than Windows Phone 7 and Android. Had Elop not been a Microsoft shill, and had he stated "here's MeeGo, it's going to be our smartphone operating system", developers would've lined up to get their applications ready for it. Nokia's massive reach would've ensured that.
And now, this beautiful platform is stillborn. This breaks my geek heart. Have fun being a Microsoft OEM, Nokia.