Very good! But then I'm an Apple geek who can't afford one!
My friend has one and they're a lot easier than a full blown Macbook to manage. If you have an iPhone, just times it by 10 for screen size, I believe the performance is likewise too.
If you get a chance head into a tech shop with them on display and have a try, 90% of the features will work, just things like Wifi may be disabled which means you wouldn't be able to get on the internet.
Like an iPhone, the touch typing and gestures may take some time to get the hang of, had the same with my Macbook Pro, but as soon as you have the hang of it you'll be wondering why other laptops don't have the same features!