I've been using it for a few weeks now. The different childish high-pitched voice that says "Goog-411" at the start of every call is really creepy.

And I've had some navigation troubles, where it won't let me interrupt the list of "top hits." Still a bit glitch-y, but better than regular ol' 411 because you can narrow a search by entering an intersection (that function isn't always presented to me, though...)