Firstly this update looks like it just copied Google's "Chrome" browser. But I'm not fussed, cause I switched to Chrome as soon as they had a stable release and being less like ie8 and more like chrome is a plus for me.
Now onto my thoughts on the new IE9. I like the new menus and bars (They have been slimmed down), its speed and performance has been improved, it can now utilize html5 which just adds extra features for web developers to add to their websites and also supports css3 another thing web developers can use to make their sites prettier.
Back to performance, this is the main reason I switched to Chrome, that and the fact that when one tab in ie8 crashed all ie8 tabs crashed. But on ie9 this has finally been fixed.
Still not quite as fast as chrome but very close.
Here are some screenshots of how the new browser looks:
I've run the beta for a little while now, and I have to say i'm quite impressed, especially with the level of integration with Windows 7. The only knock against it for me is the UI layout. Something about having what now passes for the menu bar cutting the space for browser tabs in half just seems wrong. Maybe if I use it more i'll get used to it...