A few days ago I was standing on a boulder about 25ft. above the Merced river in Yosemite Nat'l Park. While attempting to change lenses I accidentally dropped my 70-200 2.8L IS USM. I watched helplessly as it free fell 6-8ft. It then bounced off a granite rock and fell another 10ft. where it landed on another granite rock near the water. I scrambled down the bank not knowing what I'd find. After removing the lens caps and peering through the lens I discovered that no glass was broken. The only damage was a gouge in the barrel at the camera end with the o-ring a little crushed. The lens shade was also cracked.
Test shots showed no signs of any problems with focus or even in the stabilization feature.
From now on I will only use Canon for my equipment.