Recommended

The iPhone 3G runs down its battery rapidly, even on standby. This gismo charges both the iPhone and a second external battery which you can toss in your backpack or briefcase as emergency backup. Peace of mind. Works fine, well made, recommended.

Poor design, too many cables and parts to keep track of

This battery comes with: 1 battery pack (slightly smaller than an iPhone); 1 cable to connect it to the iPhone; 1 cable to connect the wall unit to the battery; 1 wall unit. So if you travel that's three extra things you need to carry in addition to the battery. Lose one part and you're out of luck. Why they didn't simply build-in the wall unit to the battery, that would have combined three items into one and would have been simple and elegant.

good and not so great

Pros:
- if I start with a fully charged brick and a fully discharged iPhone and leave them on the table I get close to a fully recharged iPhone in a little while. I haven't timed it but it seems pretty quick.
- because it uses a cord, it charges or powers any device that charges by USB. iPhone (any), Blackberry, GPS...
- you can use the iPhone while it is charging and it still charges (albeit more slowly).
- the brick is pleasantly small and pocketable.

Cons:
- requires a different (mini-usb) wire to charge the brick, so you have to carry an additional wire to recharge the brick after you've had to use it.
- connects to the iphone with a cord. It works to hold the phone to your ear and have the cord dangling to the brick in your pocket, but the cord is a pain. I like the idea of the mophie juice pack, which would still fit in my pocket or on the table or hold up to my ear, with no cord. They don't make that for the iphone 3G yet but I will get one of those too when it is available.
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