I have a simple round balance board with contact point at the middle. I've tried vew-do, with rolling balance point, that moves along the rail on the bottom of the board. It was terribly hard, I've managed not to fail for about 2 seconds... Those things are also much more expensive...
But are they actually better for building balance (for trail running, climbing etc) and training stabilization muscles? Or they are just for training balance with more fun and adrenaline?