Just to clear up some speculation in regards to Gorilla Glass 3 vs. 2 using science and official specification documentation.
The difference in brittleness (correlated by Young's Modulus) between Gorilla Glass 2 and 3 is 71.5 and 69.3 GPa respectively. This is a 3% difference, and barely any difference. Just as a comparison: glass is usually around 50-90 GPa, mother of pearl is on average 70 GPa. (lower=more elastic, higher=more brittle)
The axial stress (aka Poisson's Ratio) is almost exactly the same, 0.21 to 0.22, which can easily be down to systematic and rounding errors.
The fracture toughness (how hard it is for a crack to elongate/propogate) actually decreased from 0.68 to 0.66 MPa m^0.5, so if you have a crack in your screen, it will spread 3% easier.
And finally, the hardness of the glass did not change. It is just as easy to scratch a Gorilla Glass 2 panel as it is to scratch a Gorilla Glass 3 panel.
tl;dr - There are very little differences between Gorilla Glass 2 and 3. It should not be a deciding factor when you are deciding which phone to buy.