Internet Explorer 9 is now faster and see its all around performances greatly increased. The browser now support html5 and has hardware accelerated text, video and graphics to speed up all the rendering in your browser.
It is now also fully integrated with Windows 7 through Pinned sites & jump lists functions for example and saw is security greatly improved. For example,
Features wise, It now sport a one-box-do-it-all where you can type a a web address or start a search from. You can make website appear a application on your desktop, handy for those web app. Security wise, it is now enhanced through ActiveX filtering, Smart screen filter, domain highlighting which warns you when you may enter an insecure website and finally sport a Performance Advisor add-on that will tell you which of your add-on is sucking down all your precious memory. Finally, they remove all the pop-up notification to integrate them in IE9 Notification bar that appear at the bottom of your browser. All in all, it's a great update from Microsoft.
As a side note, if you are still on Windows XP, please install IE8 instead which is more compatible with this OS.
Notification: You will need to restart your computer after installing IE9