Be sure you get rid of any dust/work in a clean area. I wasn't really paying attention when I applied mine on my iPod, and it is very annoying seeing the dust specs on my screen. But, it is scratch free. I suppose I could rip it off and request a warranty replacement, but I'm too lazy.
Also, I don't know about the quality of their other products (audio and accessories), but the code applies towards those as well.