The Mophie JuicePack Air provides excellent protection and good battery life extension in a light package. The Mophie JuicePack Plus is the most expensive product we tested, but has a large battery.
Mophie JuicePack Air
The Mophie battery cases were large and expensive, but effective. The Air, in particular, provided outstanding phone protectionits bulk and the quality of its hard shell case (with rubberized band) just felt solid and sturdy. For whatever reason, it felt more substantive than the JuicePak Plus.
And it provided almost the equivalent of an extra iPhone's worth of battery charge. I could easily go 24 hours or more on a busy day before needing to re-charge. (Mophie claims an additional 6 hours of talk time for the Air and 8 hours for the Plus.)
The cases use micro USB to power, and the handy indicator light shows how much charge is left. An on/off switch is also a good way to manually control whether the battery is being used or not.
Mophie JuicePack Plus - Thank You Thing
The Mophie is also supposed to boost the sound capability of the phone; oddly the speakers are on the front of the case, rather than the bottom where the phone speakers reside... and yet, the sound was noticeably louder when I had the phone in the case; however, I found the sound quality a bit tinnier. Besides, I normally listen to music with headphones on.