I really don't get why anyone would want or need one? I was told to never use one, and how dangerous they can be by my instructor when I took my lessons a few years back. Even when learning I never needed one. Body dragging back to your board is easier than riding upwind! I have never, ever been unable to recover my board, granted, on the odd occasion it can be a bit of a mission, and if I lose my board...oh well, better than being smacked in the face by it!
And those GoJoe things are ridiculous! Again, why the hell would you need one? They serve no purpose at all! If your that crap, give up and choose a hobby more suitable to your skill level