I can say that the Rain-X kit actually works. I've used it several times in the last few years. Although the resin may not completely illuminate the visual appearance of the crack/chip it did prevent further growth of the crack - which was the main goal. (I'd rather live with a tiny crack that won't grow, then pay $$$ for a new windshield.) The resin comes in a very tiny bottle. It appears like transparent liquid - which you apply drop-by-drop onto the crack/chip. There's also a small suction-cup device included to help with the application. You'll need a shaded area to apply the resin, and then a sunlit area to "cure" it dry. It usually takes me about 30 minutes to do the application, and then I leave the car out in the sun for an afternoon to cure the resin. Most of the time the Rain-X kit worked without any problems. The one time the Rain-X kit did not work was when I couldn't get the resin to fill-in a stubborn crack. I was then forced to take the car to a professional windshield repair shop. But since the Rain-X kit is so cheap, it's always the thing I try first.
Cool, I will have to try to have it done soon! All glass is covered by insurance where I'm at so should be able to have the pros do it...
