Been testing Windows 8 for a few days now. My opinion is that it isn't ready for primetime. But that said, I actually like the general idea. It feels like a genuine progression is underway. And stuff like syncing from one PC to a laptop or tablet is a pretty considerable feature. Other good stuff includes the context-sensitive search - start typing in the news app to search the news, do the same in email to search emails. Some of the interface looks really nice, too.
But, I do feel like a beta tester running it, and it's all too easy to just hit the windows key + D to ignore all the new features (almost) entirely. But perhaps that's the idea? Nice big tablet-esque interface which looks nice and your gran can use, and good old Windows underneath for the angry techies.
Unless the dodgy execution shoots them in the foot, I don't think this is RIP at all.