Ultrabook
I have to admit ignorance about the Ultrabooks. Like the Chromebooks, these have seemed like non-starters to me, so I haven't even researched them. Let me tell you my reasons, and you can tell me if I've judged too quickly.
The ultrabooks run a regular desktop OS - generally from an SSD drive. While this means ultra-fast resume and boot times, and the ability to run full desktop apps, it seems that still can't match the "open the lid and you're ready to go" standby of a mobile device OS. The efficiencies of ARM type processors and mobile OS platforms seem difficult for the overhead of IA processors and desktop OS platforms to compete with.
Also - I've found that most of what I do these days no longer requires Microsoft desktop OS platforms. The alternatives are not perfect, but for most of my tasks, they get the job done. I'm largely platform independent these days. I can get almost all of what I want done on a Mac, Windows, Linux, or Android device. In fact, writing my latest article, I started on my TF300, did some editing on a Windows 7 laptop, finished up part of it on my Droid 4 in a Lapdock, and followed up with sending screen shots from a Mac Mini. There are still some things I absolutely prefer Microsoft platforms for - though, and those are generally really "heavy lifting" tasks.
I mean, there is no doubt that the weight and battery life of Ultrabooks are awesome. Really, the Motorola lapdock delivers that same kind of blade-thin format that the Macbook Air introduced, and I can see how for some users who really require a desktop OS, this is the best solution. I just wonder if it would be overkill for MOST of what I want, and not quite enough juice for the things I really need a traditional desktop OS platform for.