This power case is the best case I have in my case collection, yes, I have a few of those power cases and this product is the most convenient one of them all.
With the type of usb port it has, you can charge and connect your iphone to a pc almost anywhere.
One thing about it is that the upper part of the case that holds the iphone in (the cap) needs redesigning/to be tighter when the cap is on because its easy for it to part from the top of the case. It should "click" better and hold the case better. The other thing is the power button/lock button is a bit harder to press when the iphone is in the case. Otherwise, the case is a very, very nice accessory.