I got one of these Mr. Clean kits free through work (I work for a major Arizona grocery chain, and a vendor gave us a few samples), but I was really disappointed with it. I used it twice on another vehicle, and it just didn't work as advertised. The water sheeted off and evaporated just fine in some areas, but not everywhere.
It just seems weird walking away from a car with dribbles of water hanging all over the place. The water's as hard as a brick here in Arizona, so wherever the was a drip, the minerals in the water made sure I had a water spot. The glass looked particularly awful. Maybe this thing works better in places with softer water. As for me, I'm glad I got mine for free.