Have owned Otterbox cases since I've had iPhones and appreciate the high quality and great protection. I also own Mophie's protective case with battery, but it was way too bulky and my son gladly adopted it from me. This case has worked well; protection and battery without the bulk of the Mophie (I can put this one in my pocket, the other one is too big). The only downside is that I can't consistently figure out how to activate the battery and there's no documentation on-line. Highly recommend nevertheless.
Pros: Durable, High quality, can carry in a pocket