also, it is synchronus, meaning for things like *real time* audio, you are guaranteed that the data will arrive in a given amount of milliseconds. With USB, since it uses the CPU, if something else suddenly happens, your audio data may be delayed. This is very annoying for audio (clicks, etc) and is why all serious audio interfaces use firewire. I for one am VERY happy that they brought it back, and the 13" MBP is my IDEAL audio machine.