I've been using it as my primary OS on both my home and work desktop (as well as on several tablets - I work for Microsoft) for about the last year. The biggest issue I had with it at first was my perspective on what the native environment is. If you treat the metro home screen as the native environment, and the desktop as a secondary environment, your desktop experience wont be pleasant. While it's fine and dandy to use it the majority of the time if you're on a tablet, on a desktop those interactions don't make as much sense. When I started to use the metro home screen as purely a launcher on my desktop, things became great. I came from a linux background so I really missed the integration that alt+f2 had when I moved to windows (or spotlight if you're an OSX guy). Metro as an alt+f2/spotlight alternative is absolutely fantastic. Winkey+type anything and you're where you want to be. It really grows on you, and I'm honestly more productive on win8 now than I am on win7. As for the Metro apps, on a desktop I've found that they serve a nice purpose if you have multiple screens. I really enjoy having my mail + calendar metro apps up on one screen while I do work on my others. Just my perspective on things, which again may be heavily biased as I work on Windows.