When it comes down to raw battery power, the iPhone 4 does a good job at keeping you in the zone but it really doesn't cut it when you constantly use your iPhone 4 all day and that's when you need to call in some reinforcements. The Mophie Juice Pack Plus battery case for the iPhone 4 packs a juicy 2000mAh battery inside that's bound to get you thru your long and exciting day. Read on for the full review and a comparison between the Juice Pack Plus and the Juice Pack Air after the break.