The device paired with the recommended camera works fantastic. If you're using it to review your technique, I think it's better than a go-pro.
My only complaint is that the arm band isn't really ideal for surfing. Before I ever used it, I emailed solo shot saying that it would easily fall off and was assured their user base didn't have a problem. Sure enough it fell off on a closeout barrel the first time I used it. That's a $150 replacement part.
I've since customized the arm band so that it can't come off. Let me know if you have any questions about the unit.