I got mine today. It is true that there's a slight compression of the sound, but more importantly it does what it says on the tin, it redirects the sound to where you want it, and gives a net gain. Simple and useful.
It works with iPad 2 and 3. I should note that my impression is that the speaker on the 3 has a bit more oomph, but still there can easily be situations where you want more sound, or you want it more directed to yourself and less to to the people at the next table.
Reviews on YouTube says that it does work, though some say that the sound is more compressed in quality, less full and round.
I wonder why tablets and phone never have speakers actually pointing forwards. Is it just from the Jobsian fetish that the glass must cover the whole front?