Through all my own anecdotal evidence, I've come to the conclusion that a portion of corning's production method leaves something to be desired in terms of consistency. Throughout the internet, threads can be found that go something like:
"I thought this pos had Gorilla Glass!!!! It scratches way to $$&*% easily!!!
"My phone has been through hell with no case or screen protector and no scratches! You must've done something unreasonable!!!"
I've seen this everywhere, about almost every phone, and have come to this conclusion. Even my own g glass phones have varied wildly in scratch resistance. I still prefer having gorilla glass, but I do think it's a bit hit-or-miss.