IE8 is the poster of the word Beta.
IE8 renders everything incorrectly. IPB forums, vBullitin forums, MSN, Hotmail, Reports of Microsoft.com broken with Silverlight installed and the list goes on.
IE8 is going to be Microsoft first step into a unknown region for them. The region of Web Stanardization. They are trying to make IE8 more standardized for everyone. Trying to get IE8 to pass the Acid2 test so that it will make it easier for coders out there to code a website for general use in ALL browsers. Not have to code specially for Firefox, IE or any others out there like Opera, Safari and such.
So after the release of Firefox 3 and IE8 the Web Standards will start to take over. As all 3 of the major browsers used will be all able to pass Acid2 and be able to display pages correctly. No matter which browser you use.
With all of that said i must say that havig the IE7 Emulate button is nice. So that if you go to a site that renders horribly you can jsut go back to IE7 view. There is also a lot of more useful tools which i have yet to test out. But all in all i am rather happy with the direction. It doesnt pass Acid2 yet. Nor is it really that fast when working. But this is a step in the right direction for those of us who understand anything about coding and what it is like to have to add bits to code for rendering in IE or any other browser.
All in all i am happy with IE8 right now. Buggy as can be. Renders horribly. But it is a move forward that has been needed since IE7 was released.