I got to play a friend's copy a few nights ago. I didn't get to explore all of the options in the limited amount of time I had, but I played enough to get the feel of it. If you're used to playing an actual instrument, it will feel extremely simple. However, it does a great job of incorporating musical concepts, and would be a great introduction to music for children (or probably anybody in the general public, for that matter). I enjoyed the time I spent on it, especially the ear training exercises.
The shorter answer is that yes, I would recommend it.

I may buy it myself, eventually; right now, I have other games that I want to get first.