Here we see my iPhone 3GS inside the Mophie case and being charged by the internal battery. Just a side note - I get very poor signal in my apartment and this has nothing to do with the Juice Pack Air case. In the third photo, you can see the blue battery LEDs that I mentioned earlier. The Mophie battery was fully charged in this picture.
As for testing, I opted against doing any "hard numbers" test for the simple reason that it would be nearly impossible to get consistent results. I use my phone a good bit during the day and have no control over who calls or sends me a text, all of which would totally throw off any test results.
Instead, I decided to simply use the Juice Pack Air over the course of a few weeks. This included daily phone, text, music, Internet and email usage - basically everything I would normally do. I also took a mini vacation last weekend and used the phone extensively to keep me occupied during the car ride to and from our destination.
With a fully charged Juice Pack Air, on average I was able to give my iPhone 3GS a 65-70% recharge. As I mentioned earlier, I am new to the 3GS and it sucks down a whole lot more power than my 1st generation phone did. So much so that I had a tough time making it through a full day of normal usage. With the Juice Pack Air, I never ran into this issue, even with heavy usage throughout the day. I don't know about you, but this alone is reason to pick up the Juice Pack Air.
Aside from the internal battery, the Air also works well as a form-fitting case. Although bulky, the case has a sleek and fitting design that meshes well with Apple's phone. While it doesn't protect the delicate screen of the iPhone, it does fully cover almost every other inch of the device, preventing it from getting scratched, scuffed or otherwise damaged. I'm not too sure how well the Air would handle a fall onto a hard surface and I wasn't exactly going to find out on purpose either.
According to Mophie, the Juice Pack Air is good for over 500 full power cycles which should last the average user a couple of years at least. The Juice Pack Air has built-in short circuit, over-charge and temperature protection, is backed by a full 1 year warranty and is the first Apple certified attached battery in the world.
There really isn't too much I disliked about the Juice Pack Air. The added size and weight will certainly be a turnoff for some people who love the sleek, lightweight design of the iPhone. While I can totally see this as being a legitimate issue for some, it really didn't bother me that much. Having a larger phone to grip when texting, surfing the net and placing calls was actually quite nice.
Using the supplied USB cable, the Juice Pack Air + iPhone combo is able to interface with iTunes and charge both the internal battery and the iPhone's battery without issue. So really, there is no need to ever take the phone out of the case unless you want to mount the phone in a speaker dock or something similar.
The outer shell of the Air did get a little warm when charging the iPhone, but certainly not enough to worry with. I had no problems accessing the headphone jack or volume controls, although the silent ringer switch was sometimes a bit difficult to switch from silent back to ring. This could also be partially due to my very short fingernails.
Installing the phone in the case was very easy but things were a little more difficult when trying to remove the phone from the bottom half as there wasn't really much to grip onto when trying to slide it out. It will eventually come out, but it might take more than a quick second.
I do wish Mophie would have one-up'ed Apple and provided a cable with real-world length - you know, something longer than 33" or less than 3'. Seriously.
As of writing, the Mophie Juice Pack Air retails for $79.95 which is a bit more than your standard case, but then again those don't offer an internal battery.
If you find yourself draining your iPhone 3G / 3GS battery before day's end and a car charger / extra wall charger doesn't fit into your busy lifestyle, the Juice Pack Air is virtually a necessity. It has certainly found a home with my 3GS and won't be going anywhere anytime soon.
OCIA.net has awarded the Mophie Juice Pack Air our Silver Seal of Approval.