The sweet spot with Parallels Desktop is that I can run AutoCAD 2010 and other Windows applications on my Macbook Pro and still use my Finder or other Mac applications at the same time. Apple Bootcamp is still faster performance overall because it is running Windows natively, but you also must boot to Windows on your Mac with Bootcamp. Parallels 5 also feels much faster than previous versions in my unscientific testing. This crystal view mode blurs the lines between Windows and Mac on your desktop as it shows none of the Windows OS UI.
The new version of Parallels Desktop 5 for the Mac OSX has a new crystal view mode. OK so it is not a native Mac version of AutoCAD, but pretty close.