Just for S&Gs yesterday I decided to impress a friend and scratch up my GA-protected screen with a key. I didn't press super hard but I did enough that would have made permanent scratches on an unprotected screen.
So the result of the test was that I got some very light indentations in the Armor where I had scratched, but they were only visible at certain lighting angles. I wondered if they would stay on there. Next morning I checked, and they were pretty much gone.
I won't be doing "infomercials" for people any more, but it's nice to know that the product does what it claims.