I agree never under estimate a servo skull! Back when the Daemon Hunter Codex was still really new I played against a buddy of mine and he rolled up a generic greater daemon to use in his SoB army. My Inquisitor and retinue came into close combat with the greater daemon and after a round or two of combat the servo skull was the last man standing in the fight and ended up inflicting the final wound on the greater daemon and killing it. Needless to say we were both amazed.