Looked at the demo video just because. While it seems to make the large drop of water roll off with ease I didn't see anything at all that gave me the impression that this would work any better than rain-x when it comes to dealing with lite spray. IMO It's the lite stuff that is the problem... big drops are no big deal if your shield is in good condition.
I thought rain-x was a no-no on plastic?
Maybe a chicken is just an egg's way of making more eggs.