ok i'll base my judgment on the recording of her voice, i give it a 5 because of the loud projection, and the consistency of her voice, it's solid and graceful. i can forgive her for lip syncing since it's necessary doing that since they have to compensate for unequal sound reverbarations that takes place in a live environment, the best voice will sound crap when there are too many elements competing with it like claps, and cheers or other noise coming from mechanical equipment.
Miley is definitely a 5 star.