This is one of those things that sounds sorta gimmicky and is easy to knock off as worthless. But I think there might be something to stuff like this.
I tried a few of brain sync's products (
Brain Sync Brain Wave Therapy | Mediation, Relaxation, Mind Expansion and Self-Improvement) a while ago, and while not revolutionary, they definitely had at least some noticeable affect, which was kinda cool to experience.