I just submitted a review for the Mophie Juice Pack Air on Amazon... since it is not visible yet (waiting for approval), I thought I'd copy/paste it here for people to read.
Suffice it to say that I'm REALLY disappointed in this thing... especially for its price. Here's my review...
I'm going to be going on a long flight soon and wanted a little bit of extra life to my 3GS. Figured why not get that in a full case that I can turn on and off as needed? Great in theory...
One MAJOR flaw though. You lose all kinds of service with this thing on (not even turned on, just physically attached to your phone). I had read a few reviews stating that it can affect your service - but really just assumed that it was a bar or two. That would be doable if I was still able to get signal... but worthless when it kills it completely.
I'm sitting at my desk now and with the Mophie detached and the phone sitting on my desk, I get 4 full bars of 3G service. When I attach the Mophie and put the phone back down on the desk, in the same exact place, I instantly get No Service. How is that possible? Like I said, I could understand losing a bar or two... but EVERYTHING? No way... not cool.
If that weren't bad enough... I'm actually not even happy with the rest of the case design. If you flip the silent mode switch, you can barely reach it to turn it off. I ended up using a tiny screwdriver. It also bothers me that there's so much open space at the bottom of the case to allow dirt/dust to get in between your phone and the case and scratch things up. Why can't it just fit well if it's not going to work?
The only saving grace for this (and why it gets 2 stars instead of 1) is that in my specific situation, I will still get some use out of it on the plane. Once I turn turn my phone on to Airplane Mode, I can attach the Mophie and not care about the signal while on the plane... but other than that it is totally useless. Do not waste your money.
There you have it... this is a definite skip. Do not buy. Bad product. I'm NOT happy. I may even write to Mophie customer service about this (politely). If it weren't for still being able to use it while on the plane, I'd be REALLY pissed.