I have now done some initial testing and evaluation of the 6801 build of Windows 7, which we got at PDC 2008. First of all I was a bit disappointed that we did not get the updated UI that were shown during the keynote, instead we got a previous build that does not have that much changes in the UI.
It boots pretty quick on my Virtual PC, yes I run it there – a little to early to switch out my main OS, and it has a nicer loading screen than Vista.