The problem isn't so much the Gorilla Glass failing as it is the glass components of the AMOLED on phones such as the Galaxy series. My Captivate, much like my previous Attain, both suffered screen cracks that left a spotless Gorilla Glass digitizer behind, as if nothing happened.
I've come up with a bit of a theory as to why this occurs as well. Much like resonant frequency literally shaking a wine glass to shards, the Gorilla Glass disperses much of the kinetic energy of impact by transferring it throughout the rest of the phone, where it has a higher probability of causing damage to the un-reinforced glass of the screen below.
In terms of scratch resistance however, I'd emphasize "resistance" as I know for a fact that Gorilla Glass will scratch, often times starting off as micro-fine lines and over time getting more noticeable with entropy.
So far, the best solution I've found for my current phone is a good case and screen protector combo, specifically Ballistic "Shel-Gel" and Zagg, respectively.
I've dropped my Galaxy Nexus flat on its face on numerous occasions, and I've noticed that there's a much more effective dissipation of kinetic energy with the extra layer added. I've even noticed scratches that were there on the screen protector one day and gone the next (I think I had put my phone in the pocket with my keys by mistake), so I'd definitely advise that screen protection is cheaper in the long run than having to buy screen assemblies (the Captivate is lucky and has a separate digitizer, but the new technology Samsung utilizes to create Super Amoled and HD Super Amoled screens is almost like printing the pixels onto a glass surface, meaning the entire screen is only replaceable as an assembly, as I've learned from repairing my Attain's cracked screen.)
Hope this helps!