A report that surfaced from SquareTrade a couple days ago claims that accident rates are higher on the iPhone 4 than its 3GS sibling.
SquareTrade says that in the first four months of the iPhone 4 being out in the wild, there is an
82 6 percent increase in reported broken screens over the rate on the 3GS. Thing is, SquareTrade counts the back of the iPhone as a screen, not just the front display, and reports that broken glass on the back of the iPhone accounts for 25 percent of the issues they've run into.
One thing to take with a large grain of salt -- SquareTrade makes its living by selling warranties. It culled its numbers not from AppleCare, but the company's own warranties that it sells. Far more iPhone 4 users most likely have AppleCare or no extended warranty at all on their iPhone and this study, which has grabbed a good bit of media coverage, seems to have been created to sell more of SquareTrade's warranties.
There was also a pent-up demand for the iPhone 4 as evidenced by the numbers sold compared to those for the 3GS. Many people, myself included, waited to upgrade from the original iPhone or iPhone 3G and never got a 3GS. The phones are also constructed differently. So, take double the amount of glass in a phone, add the fact that there are more phones out there, and you're going to have more accidents. Read through the report and make your own decision. If you're still worried, slap a good case on your iPhone and don't use it as a hockey puck or bottle opener.