I originally purchased one of the Mophie case/charger and they are the the leaders in the field. However on my 3GS was easy to break and battery life decreased considerably.  So much so that I was origional agains this purchased and went for the Third Rail Product and after a overheating problem I sent it back. Amazon was great concerning this and other matters and I believe this company to be very fair.  I received my Mophie for the 4S and noticed it definitely weighed in as having a big battery.  The case i s beautiful  however some improvement I hope will be forthcoming in the new unit.  The mini USB that comes with the Mophie has a lot to be desired and I recommend a longer cord from Amazon. The case adds a little difficult on reaching the buttons and the USB in in a good location.  Mini-USB's are notorious for being delicate and in my experience lead to poor connections.  The LED battery lights are bright and are certainly easy to see. A bit small and a blue LED WOULD BE PREFERRED.  I have only had this case and will get back with you after two months for an update.
I originally purchased one of the Mophie case/charger and they are the the leaders in the field. However on my 3GS was easy to break and battery life decreased considerably. So much so that I was origional agains this purchased and went for the Third Rail Product and after a overheating problem I sent it back. Amazon was great concerning this and other matters and I believe this company to be very fair. I received my Mophie for the 4S and noticed it definitely weighed in as having a big battery. The case i s beautiful  however some improvement I hope will be forthcoming in the new unit. The mini USB that comes with the Mophie has a lot to be desired and I recommend a longer cord from Amazon. The case adds a little difficult on reaching the buttons and the USB in in a good location. Mini-USB's are notorious for being delicate and in my experience lead to poor connections. The LED battery lights are bright and are certainly easy to see. A bit small and a blue LED WOULD BE PREFERRED. I have only had this case and will get back with you after two months for an update.