Often things that seem like a good idea in principle disappoint in reality. Not so the Mophie battery case for iPhone. I've had mine for 6 months and it is fab. It won't suit at all if you're all about image, and the main reason you have an iPhone is for its uber-slim good looks. But if you're more interested in functionality, this add-on is perfect. It makes the phone chunky, but that's a small price to pay for how well it works.