never really had bad head, just lesser degrees of good. Oddly enough each girlfriend i've had since i've been (oral) sexually active has been better than the last at giving head. My current gf loves it and she does the whole shebang swallows, ball attention, deep, licking, using hands, etc. It turns her on as much as it turns me on.
sorry for you guys that have had bad experiences, nothing but good here.