I bought the Mophie Juice Pack Powerstation to use on the plane for an upcoming trip to Singapore. Before leaving town, I decided to test it out, and was very disappointed.
First off, using my iPad charger as the manual suggested took at least 5+ hours to charge the Mophie. I would tolerate this as I would have time to charge it overnight. However, when I used the Mophie to charge my IPhone 4S from a fully depleted phone battery, it took 3 hours and used at least 75% of the Mophie charge up. This is a lot less than the 2 full charges claimed by Mophie web site and other reviews.
After fully charging the Mophie again, another 5 hours, I tried it with the new iPad (3rd Gen). After three hours charging the iPad, the battery was up to only 22% (from zero) and the Mophie was exhausted. The bottom line is it took a total of 8 hours to charge the Mophie and transfer the charge to the iPad, leaving a charge that is sufficient to use the iPad just over two hours.
Needless to say, tomorrow I am returning the Mophie to the Apple Store.