Does anyone have any idea about the long hair safety of these products like these?
http://www.johnfrieda.com/products/products_main.asp?section=products&subSection...

They seem to be a safe way to enhance color since they don't penetrate deeply.

Any experience?

The product info says that it is a dye that penetrates the cuticle, so it is a permanent color, but does not have peroxide, so it does not lighten or strip existing color.

Regular re-application is necessary for the shine/glazing which appears to be a water soluable silicone type product.

I'd put this product in the catagory of better than permanent hair dye, but one that could possibly still damage the hair.