I have tested the stable version 4.3 on windows xp and unfortunately, KDE for windows is a sad shadow of the linux desktop. I cannot recommend it at this point. Why? I expected to boot into a graphical logging interface and choose KDE as the option. But only I could see kde applications, which always start slower than the windows counterparts. Not to mention things such as dolphin not being able to show my USB keys (have to create a device folder manually each time !!!)

Yes, it's "merely" the nearly complete KDE suite of applications for Windows, not an actual replacement for the Windows shell itself. Still, it runs NATIVELY under Windows and is NOT shell dependent! This is a huge advantage once you understand the implications of this; it means even if your Explorer crashes repeatedly, your registry is messed up and you've got some 100 BHOs installed, it won't affect Dolphin or the rest of the KDE apps in the slightest. Yet all your installed fonts are available, your C: drive is local (and called C:) and there is no need to learn how to install and use things like Cygwin or Xming or Virtual Machines to achieve the same result. What this all means is that unlike similarly intended ports of Linux applications to Windows, this is the first one that really is as easy to install and use as any other Windows app. You don't need to know a thing about Posix, Bash, Consoles, Python, CIFS, etc., and that's the point! Finally, some of the apps are just slick; take one look at KCharSelect and you'll wonder how you managed to get by all these years with Window's crappy version.