Despite there being some much lower-priced competition out there in the iPhone battery pack game, Mophie’s Juice Pack still reigns supreme (but just barely). At $100, the Juice Pack is a tough choice for many folks who spent only twice that on the iPhone itself, but given how addicted many of us have become to the various games and applications on the iPhone, an external battery pack has become a necessity, and the Juice Pack is still the coolest of them all.