I don't have the Mophie power station, but I do have a Mophie Juice Pack Air for my 4s -- I like it. The Mophie iPhone case is a reserve power source if the switch is in the red position. In the green it's on and charging the iPhone continuously until it's depleted, so the meter on the iPhone will show 100% until the Mophie starts to deplete. I keep it in red so the Mophie maintains a full reserve charge; switch to green and it dumps into the iPhone.

Nice thing about the Mophie is it takes a standard mini-USB connection and isn't as selective with source. The Goal Zero solar system plugs into the Mophie to recharge the iPhone. I haven't used the proprietary Apple connector in years.