I recently bought a crystal film set for my iPhone, I believe it's made by Power Support.
I was of course a little paranoid about scratching my screen so I decided to invest in this. I must admit that in the past, I've had trouble installing these type of films on my screens, but this brand seems to work really well. I don't even notice it on my iphone. Fairly easy to install. I also find it a lot easier to wipe off any fingerprint smudges.
I guess with this crystal film, I have a bit more peace of mind knowing that I at least have another protective layer.
I hope this helps...