It's nearly a third the weight of a MacBook Pro, you can stick them in your jacket pocket (the iPad Mini is barely wider than the keyboard), the keyboard is full-size and you can rest it on your lap for ergonomics, and as long as you're just dealing with writing text, the screen is plenty large enough.
(And the keyboard lets you do all your cursor positioning with the arrow keys, literally no different from a laptop.)
For programming forget it... but for writing, it's the best thing I've ever found.