The Lenovo Yoga Book is... odd. When it was announced in September, it was very different from any laptop or convertible I had seen before. Instead of the standard keyboard and touchpad combination, the bottom panel is a giant Wacom digitizer for sketching and taking notes. When you need to be productive, the bottom panel can switch to the 'Holo keyboard,' a touch keyboard and trackpad in the typical laptop layout.
Now that reviews are out, what is the general consensus? Everyone who has tried it remarks about how amazing the device looks in person. LaptopMag called it, "one of the most beautiful pieces of technology I've ever laid my eyes upon," in their review. The largest issue with the Yoga Book, as you probably could guess, is the Holo keyboard. "After a few days of using the Yoga Book’s keyboard, I still don’t feel completely used to it," the Verge said in their review.
The Yoga Book is available in both Android and Windows 10 configurations, and the Android version isn't perfect. It comes with Android 6.0 Marshmallow, and to help with the lack of multi-window support, it ships with Lenovo's Book UI skin. As you can imagine, the multi-window functionality is nowhere near as good as the feature on stock Android 7.0.
The Verge listed some popular applications that do not work with multi-window, including YouTube, Google Docs, Twitter, Slack, and Kindle. Lenovo told PCMag that they intend to update the Yoga Book to 7.0 Nougat in Spring 2017, which will hopefully alleviate this problem.
Both editions ship with an Intel x5-Z8550 CPU, 4GB of RAM, and 64GB of internal storage. The Yoga Book is also short on ports - only including a microUSB charging port, an HDMI port, a headphone jack, and a microSD card slot. I can't find any mention of USB-OTG support, so connecting standard USB devices may be impossible with the Yoga Book.
Still, if you are in the market for a convertible and you don't mind a touch keyboard, the Yoga Book may be for you. The Android model is $500, and the Windows 10 model is $550. Right now, it looks like the only place you can buy them is from Lenovo's website.