Well, no one mentioned it yet so I'll bring up my dislike for the stuff, based on my experience which is that anything you put on the dash (or the seats for that matter) will evaporate over time and wind up leaving a film on the inside of the windshield. I don't like having to clean the glass when that stuff is in a car. it makes a hard job even harder.
Besides that I covered the dash on three of my cars (the ones with non cracked dashes) with dash carpets so I don't need to use any spray stuff on those. the others are so cracked its senseless to wipe them with anything less than a garden rake
