SquareTrade, a company that does third-party warranties for consumer devices covering accidental damages, released analysis of data comparing accidental damages to iPhone 3GS to the iPhone 4. They found that the iPhone 4 is nearly twice as likely to have accidental screen damage than the 3GS as reported by users submitting claims.
After four months, 3.9 percent of iPhone 4 owners reported cracked glass. That's an 86 percent increase over the percentage of iPhone 3GS owners (2.1 percent) that reported cracked glass within four months of ownership. SquareTrade attributed this increase in chances of accidental damage to the fact that the front and back of the iPhone 4 is made out of Gorilla Glass. The iPhone 3GS is made out of a plastic material which is more resilient to accidental drops.