Make no mistake: Lenovo is taking this Windows 8 thing very seriously. The company's first-generation of Win 8 devices includes everything from a laptop / tablet hybrid to a classic convertible laptop with a swiveling display. Then there's the Yoga. This, too, is a convertible, in the sense that it can be used as a tablet. But it's not like any convertible you used back in the Win 7 era: the screen folds 360 degrees back, turning this Ultrabook into a giant, 13-inch slate. Because of that special hinge, though, you can also bend it into Downward Dog, to use a Yoga term ("tent mode," if you're nasty) or fold the keyboard underneath so that only screen is exposed. It was one of the most memorable things unveiled at CES, and it remains the most striking Windows 8 design we've seen to date. But what's it like to actually use it? And how does it fare as, you know, a plain old $1,000 Ultrabook? Let's find out.