According to the information available about the products, the paint coating is for paint and the surface coating is more of a wide spectrum coating that can be used on paint, plastic and glass.
I'm a user and a fan of the PBL Surface Coating and as soon as I get some time I'm going to re-coat our MB with it.
This question seems to pop up about once a month. I like the paint coating, but have never used the surface coating. I have always wondered how the paint coating would work on other surfaces.