[Wayne Luke]

Its standard compliant to CSS 2.1 (passes Acid2), XHTML 1.1 at this time. It doesn't require coding tweaks like IE 6 and 7 do. Microsoft worked closely with the Web Standards Project to make this happen. Its a shame they didn't add more CSS3 or HTML5 support but the big users of Internet Explorer are corporate Intranets which are about 5 years behind these recommendations. There will be some problems with bleeding edge websites but really shouldn't affect the majority of design.

For the vast majority of websites, this is a huge step forward though. As the corporations upgrade, so will their employees and you can ditch IE6 support and embrace better CSS and things like PNG images without having to worry about workarounds.

Operationally, IE8 is slow to spawn new tabs. I think that is an architectural issue in Windows more than IE though. When you create a new tab in Firefox, it creates a new document within the same application. When you create a new tab in IE, it spawns a new instance of the application and shows you that in a container window. Since the new application has to be sandboxed, it is slow. This provides some good features in Windows 7 but does come at a cost. The scripting engine is a little slow as well. Most people won't notice but it could use a parsing update. Of course since it uses Windows Scripting Host, it would require an update to that as well as the .Net framework.