I would almost agree with this for iPhone 3GS, but due to exposed glass edges on iPhone 4/4S this is no longer the case - coming from someone who's dropped and

I would almost agree with this for iPhone 3GS, but due to exposed glass edges on iPhone 4/4S this is no longer the case - coming from someone who's dropped and cracked his fair share of iPhones. The bumper case is enough to protect the edges of iPhone 4 from the impact - which is where the crack first forms and then explodes all over the glass plate.