My iPhone 5 fell out of my pocked (forgot to zip it) while riding yesterday at approx. 20+ mph. There was a substantial gash on the corner of the case where it hit, but the phone appears fine.
The case is also waterproof and I often notice that sweat vapor often collects around the screen. I used to pack my iPhone 3GS in a plastic while riding and that phone died a slow death largely, I believe to moisture, which is why I'm trying this one.
The case is by Lifeproof and I thought I'd pass my story along. It's not perfect as the touchscreen is not as responsive as a result of the enclosed cover so that presents an added challenge for my already poor typing skills. For someone who is pretty hard on phones though, this case is serving me well.
The company's claims are that the case is waterproof (I tested by submerging the case in water for an hour before installing); and shockproof up to 2 meters. So far both appear valid.