I bought one yesterday, and from playing around with it in sim mode, and planning flights it is extremely easy to use, but powerful.
It does get charged up by the USB socket, I think the iPhone AC charger should work ok also.
The Garmin website for products (where you update the terrain and maps database) is fantastic, hooked it up on my Mac (PC's work too) and it downloaded the plug in and updated my maps and terrain painlessly