Internet Explorer finally gets CSS3 and HTML5 features. Including CSS Border Radius:
Internet Explorer 9 scores 55 out of 100 in ACID3 test, which is better then IE8 but still not as good as other browsers. So it appears they have more work regarding web standards. MS included a graphic with WebKit SunSpider javascript benchmark results:
More on MS webpage (including download). It will not overwrite your existing Internet Explorer. But be warned, this is in through sense a preview so don’t expect much. And one other thing, you might miss some ordinary browser features like address bar, you can see for yourself in the first picture. :-)