I would recommend against it.
I have it installed on my iPhone 5 and it is not just a smudge proof screen that gets smudges, but it also a glare reducing protector - this results in the screen looking less clear. If your fingers are at all oily when touching it, it actually is more noticeable because of the way the light is reflected from the display.
Also, the cut for the camera looks sloppy, it is not centered at the top and is a large triangle cutout. Finally, the screen protector does not fully extend to the edges of the glass or any average case, so there are a couple millimeters of glass exposed between the screen protector and other cases you put on.