From Sept to Dec, I used WDP side by side with Win7 SP1... But since the last month or so, I'm using it in a VM (VMWare Player; can't install it in VirtualBox 'coz my processor doesn't support VT-x) I suggest you wait for the Beta and install WDP in a VM.
My CPU also doesn't support VT-x so only way to test WDP is install as main OS, Dual OS or to find Virtualization software who doesn't require VT-x
As of now, only VMWare Workstation and its free alternative VMWare Player lets you install Win8 without needing VT-x.
I trust Jaycee, so after she put up the build-string, I post about it in PCBeta & Neowin within 5 mins........ LOL, all hell broke lose
Because the build number is (generally) incremented everytime there is a compile. So the reason for the build jump is most likely because of last minute bug crushing.
Little Secret: In the Windows Developer Preview, start Windows Explorer and go to "C:\Windows\Offline Web Pages". The Ribbon will desappear and the Windows 7 Toolbar will be in there.
Wish I could somehow have the Aero and all the aero-related changes of Windows 8 in Windows 7..!! That would be so great! I will skip Windows 8 then!