The Good: The PlugBug provides 10 Watts through its USB port, whereas normal/high-powered USB ports provide 2.5 Watts/5.5 Watts. This allows quick iPad/iPhone recharging, even when your iDevice and laptop are both in use. The PlugBug connects nicely to your laptop power adapter, and together they are very easy to pack in your bag. You can even connect the PlugBug to Apple's AA battery charger or to another Apple 10 Watt iPad charger! The dimensions of the PlugBug are aligned with the dimensions of the Macbook Air's 45 Watt charger, and together they are about 40% larger than the Air's charger by itself. Finally, the combined PlugBug and charger takes up only one wall socket, which can be convenient at hotels and crowded cafes.
The Bad: The PlugBug prevents the use of the 3-pronged extension cord that connects to your power adapter. Thus, you may have to sit six feet closer to a wall socket than you did before. The combined PlugBug and laptop charger doesn't save much overall space compared to a separate 10 Watt charger and laptop charger.
The Ugly: The PlugBug emits a high-pitched whining/buzzing sound that is faint but persistent. If you are working in an environment with ambient noise like a cafe, then you will not notice it at all. However, if you are using it in a perfectly quiet environment, then it can be as annoying as a mosquito buzzing in your ear. Hopefully Twelve South addresses this issue with subsequent iterations of the product. (My PlugBug was purchased at an Apple store near the end of 2011.)