I have contemplated getting the deflector but I recall on my old acura that it was a pain in the ass when it cames to washing the car. everytime i soap up the car and rinse the deflector would get in the way of hosing everything down.
For the folks with Moonroofs, do any of you have the deflector?
http://mazdagear.com/moonroof-wind-deflector---cx-5.aspx
Does it help at all?