I am trying to decide between the Otterbox Defender and the Griffin Survivor. With regards to the environment - I'm a quality engineer and a large portion of my job is spent in a manufacturing environment. I use my iPad extensively for my quality audit checklists and writing reports while on the floor. I would like something that could survive a fall from a product sampling table (roughly 3.5 feet) or out of my hands while walking, down onto a concrete floor. Which is the preferred case?