It actually works! :-) Well done. Truly first class CSS support in Microsoft's browser. Renders complex CSS designs flawlessly out of the box. I, for one, am elated.
I haven't been able to dig into the scripting side much yet, but the rendering improvements are truly impressive. The half-finished product we saw with Beta 1 is definitely more polished and refined. The few regressions that I noticed seem to be fixed. And dare I say it, IE8 seems to be on par with Safari, Firefox, and Opera, at least in terms of CSS support. Of course the other browsers are still eons ahead with preliminary support for complex CSS 3 features, HTML 5, canvas, etc. And they've barely touched the scriping engine. At least they are working to plug memory leaks and make JScript processing faster.
The ability to switch between the IE7 and IE8 engines is also pretty cool, very seemless, and about as usable as a feature like that can get.