Peter Bright does a great job covering all of IE 9. One thing that I think is pretty nice is the way tabs are handled, they take up no extra vertical space. They are not on the top or bottom of the URL bar (Chrome is top, Safari is bottom right now) rather they are inline with the URL bar. This looks nice and like I said takes up no extra vertical space (which on our widescreen computers is precious), though the major downfall is how many tabs you can realistically deal with before they become too small.