My iPhone 4 (S) with a completely empty battery is fully charged in just 3 hours. Then I joined the Power Tube 5500 to the iPad 2. This was at the time a capacity of 49%. The Power Tube 5500 managed to load the iPad 2 at least 77% more, until he was finally completely empty. I think a respectable performance.
Immediately the Power Tube 5500 is next to the iPhone and iPad my regular companion.