Written on: 10/07/2012
In terms of physical size and weight, I'd place this at about the same weight as a cell phone and a bit larger than a couple of 9-volt batteries stacked on top of each other. You can easily wrap a hand around it, or slip it into a pocket, and the weight is enough that you'll know it's there.
The main thing you should care about with a product like this is how much of a charge you can get from it. My cell phone is the Samsung Epic 4G, and has an extended battery installed. This pack was able to charge it from around 25% to 100% over an hour or so. It did that twice, and charged my brother's Motorola Droid once. Then, it provided maybe 20% of a charge to a 'New iPad' (a.k.a. an iPad 3). For the size, weight, and price, I was pretty impressed.
There are two "tricks" to using it. The first is that to initiate a charge from the battery to your device, you need to connect the cable and then press the button on the front of the battery to start the charging. Press the button twice quickly (like a double-click of your computer mouse) and the flashlight turns on (or off). The flashlight is a single, bright white LED and works well enough for basic needs.
I haven't measured the time it takes to charge the pack itself. When I've used it, I've just plugged it in and charged it overnight.
The charging port takes a standard micro USB cable. For my phone which charges with the same port, that's perfect. It means that all I need to carry is the wall plug and my normal USB charging cable for my phone to use it on the go. (Plus the iPad cable if I plan to use that.) The battery comes with a bunch of other plugs that, honestly, I will likely not use.) The row of blue LEDs on the front provides an indication of the charge left in the battery, or of the state of charging. While charging, the (fairly bright) blue lights will flash to show that it's charging and to indicate the charge level. (This might be annoying in a dark room where you're trying to sleep, but you could easily solve that by turning it upside down or putting something over it to block the light.
It's a nice looking product, at least to me. It feels solidly built, and has performed well in three months of ownership.