The USB bus has been a boon for computer device manufacturers. No matter how simple or complex their devices may be, there is a relatively simple connection standard that they can all use – Universal Serial Bus. The only problem with USB is that it is a master/slave bus which requires a USB host controller and those have historically only been installed in the computer itself. Sharing a USB device could only be done if the device was connected to a PC. If that PC is turned off or unavailable, the USB device is too.
Check out the full review over at EverythingUSB.