Ceramic Coatings for paint.

Hi, as anyone had this applied to their car? A few detail guys around here are swearing by them. I just had my Demon striped and repainted @ 16 months ago, so I was leary about this, so I wanted to throw it out here and see if anyone has any experience with it. The detailer told me he had to take a course to be "Certified" to use this product.
Thanks
Tom