I don't have strong experience with that particular nerve, but I've been kicked on the side of the neck during sparring without any real effect. I was surprised once that a hard strike to the nerve running down the side of my leg could make me feel dizzy though. As far as effectiveness goes, if you hit it hard enough in the right spot, it should be fairly effective. You shouldn't be doing that unless you feel justified in injuring the person. I wouldn't say it's a better target than the temple or jaw though.