New to facial animations, should I use joints?

I am using a program called Faceware in Maya to animate a “game ready” character that uses bones for its face (eyelids, mouth, jaw, eyes etc). I have managed to make it speak and in future I will improve the animation.

I was wondering, is it better to use joints for faces when the NPC is talking? Or should I go about another method?

And another question: Is there a difference between game performance when using joints or morphs for animations?