FADEC is the "fly by wire" of engine controls.
Unlike PMC or EEC there is no cable linking your thrust lever to the control unit in the engine.
Other than that its just an advanced FCU. More efficiently controls fuel flow, variable guide vanes etc.
Oh, and the best bit, when you line the thrust levers up, both engines will produce exactly that same amount of thrust, no matter what. No more staggering the thrust levers!!