I have a mystery scratch in mine already, I have no idea why it happened or where it happened. I leave my phone in a pocket by itself when I carry it around it sucks. I really felt it it was going to ruin the whole phone for me.
I went and got the standard screen protectors from verizon (not the anti-glare ones) and I'm hoping these will stop a another one from forming. These ones aren't as bad I as feared.
My point is it's definitely not as tough as the glass in phones with corning gorilla glass