Contrary to another review I read here, the "assistance sticker" just made sure that I applied the screen protector correctly.
You must of course first make sure that your screen protector itself is correctly positioned before you stick the help sticker.
Unfortunately, 1 small dust thread slipped in after I wiped my screen with the included alcohol wipe.
When I "tap" in this place there is an audible tap, but it hardly disturbs during normal use. Only noticed it while I was playing Jetpack Joyride. :)
Other than that I have nothing to complain about. Yes, because this is a glass screen protector, it is a bit thicker and the home button collapses a bit. But I honestly think this feels more fun than before.
I was also not sure if my iPhone's fingerprint feature would still work after I put the corresponding home button "sticker" on the home button (to bring it back to the same level). Nothing further is explained in the instructions, so I just left it that way.
I can't speak to its durability yet as I've only just started using it. But it feels just like the original iPhone screen, and I'm very happy with that.
All in all a good purchase. I'm ordering another one for my girlfriend.