I've been using W8 as my main OS for about a month now, and I don't really have any complaints (switched from Mac OS Lion). I can do everything just as well as I could before, although I admit I'm not a power user. I just use an Internet browser and MS Office 100% of the time.
I just wanted to say that I'm mystified as to why MS thinks a device that is a tablet, then becomes a laptop when you add a keyboard case, then slots into your monitor and KB/M and becomes a desktop, is a good idea. All that plugging and slotting sounds like a pain, and all those cases and shells will be useless if I lose the main tablet unit, or if it breaks. And why bother with so many dumb shells when CPUs, memory, and storage are all far cheaper than they've ever been?
What I really care about is my files and data (music, photos, documents for work, contacts, browser bookmarks, etc), not the computer it's running on. What I would love (and have yet to see from MS, Apple, or Google) is a cloud system that really works transparently, flawlessly, and instantly. My devices should all be windows on my data, and they should all show me the same data all the time. Additionally, each device should have an interface that is precisely tailored to it, and only it.