I use it on my netbook, which goes more or less everywhere with me. It's not only far simpler for, say, my dad (who is still slightly unsure whether computers fall under the realm of science or witchcraft - both being bad), but it also makes things easier for me. You can read that as "one less click to get into emacs" if you want.
But on a serious note, the actual interface of the OS seems to be far less important for tech-savvy people. I'm using Windows 7 right now, alt-tabbing between a web-browser and emacs (finally getting around to exploring Clojure, if you're interested), and would be doing exactly the same if I'd booted into Linux this evening instead. 'Computer people' know what they want to do on their machines and do it; and cross-platform is king for 'their sort of app', these days.
My dad, on the other hand, thinks that computers are largely operated by shout-recognition. He'd love an iPad. He can point at the thing, it does the thing - he's not prepared to learn, to know or to think about it. That's the market Apple will be aiming for; people who view computers as being more like toasters than toolboxes - that thing they use to do that thing. And people love toasters.
However, I genuinely believe that the likes of UNR offer a far better compromise over-all, because most people start out with flailing and shouting - it would be an awful shame to deny them the tools to move beyond that, should they be so inclined.