I had DefendAll protection film on most of the impact areas of my last car, and it worked a treat. In 5 years, there was not a single stonechip where the film was applied.
The film could be polished with decent detailing products and you'd struggle to tell it apart from the unprotected paint...but if you weren't careful when polishing you'd get a line of polish at the edge of the film.
Once on though, it didn't move, didn't yellow (I don't think...it was on a yellow car!) and just worked.
I think it is a 3M film Defendall use.