I have never though any kind of a screen protector was a good idea. As the guy at the Apple Store told me, the iPhone has the highest quality display out of any mobile device in the world. No matter how clear the protector is, it will always distort that at least a little bit, ruining the point of the retina display. As far as the tiny scratches people are getting on their phone, the front screen rarely scratches and when it does, its so small you can hardly tell when the phone is off and you can't tell at all when it is turned on. For the scratches on the back, you can pop a case on, or if your like me and have no case, if it somehow gets scratched you can get the back replaced by Apple for about the same cost as this screen protector.
The real problem with iOS screens is getting them smashed, and no screen protector would ever stop that (especially a glass one).