My opinion is that the documentation, which contains at least one example program, is adequate, though some exposition to wrap around the bare descriptions of the API would be welcome. I have to say that there seems to be a complete absence of end-user support for this product, which is very disappointing, since I have been unable to successfully generate the NDK++ package. As such, I have to change my original rating to "useless".
Desperately needs a tutorial/introduction and better API reference docs to be useful (to me at least). The code looks pretty nice though at a glance. Thumbs down only because it wasn't usable for me without real documentation, not that the library is "bad".
There are no 4 star reviews.