I personally hate putting cases and screen protectors on my phone, but not as much as I hate seeing a scratch on the screen.
The Power Support Crystal screen feels and looks identical to the iPhone screen, no 'orange peel' or stickiness like you get with the wet screen protectors and no adhesive, it just sticks to the screen and you forget it is there. It does not effect the sensor like some screen protectors do and the retina display looks exactly the same with the protector in place.
Application is really easy, line it up and just place it on the iPhone screen, no air bubbles and it is ready to use right away. I like that they include a cleaning cloth and a sticky film to prepare the surface of your phone before you apply it.
Not cheap, but really worth it to protect the screen from scratches.
The pack includes 2 front screen covers, one back cover, a sticky film and a cloth.
I use this along with the apple bumper and it is a relief to be able to throw my phone in my pocket with keys and change and not worry about picking up scratches.
If I really wanted to find something to improve on this product it would be to include two back pieces as well as two fronts.