I bought this as I commute, and always take my Livescribe pen to work. Availability of spares is low in the UK, and a replacement dock like the one you receive with the pen is, as I recall, of a similar price.
The Pro Charging Cradle is very nice - weighty enough to not get easily knocked of your desk, but quite small. The body is made of aluminum, except for the actual docking area. A plug with adapters for Europe (and I think America) is provided so you can charge it without turning the computer on, although you can just use the USB (although this will not provide enough power with a USB hub (unless the hub itself is separately powered)).
A word of warning though, if you leave it plugged in just with USB, and turn your PC off but leave the pen in, the pen will not turn off (in fact if you dock it when there is no power going into the dock, it will also turn on). Depending on what you have the auto off time set to on your pen, this may drain the battery.