Having watched and helped someone new to programming with this (anecdote of one), I think it's a fair introduction to Python, but not a good introduction to programming. Best if you bring at least a small amount of experience.
I don't know, to me it seems like any amazing way to teach in a TDD fashion. It seems like you could use the assert messages to help provide clues to make it more of a learning experience as well.
I think the next step that would be super cool would be to turn it into a web app so there would be no install. Instead you'd be given the single Koan to solve and work your way through them all.
Replying to myself, but the comments actually seem to do a pretty good job of teaching, so my comment about adding more to the assert messages probably isn't really needed.
