I put one on my Xtec and it took a very noticeable sound out of the setup. I would recommend it! All bows aren't the same as to how far off the string you set it, so you might have to play around with it a touch. And also to make sure you serve the string where the stopper is going to hit! String wear will occur if you don't.
If you are interested in picking one up, let me know(shoot me a PM). I know of a gentleman that makes his own and it will save you a few bucks.