Well, I've looked at this thing before, because my fibro makes me less inclined to do actual workout than anything else. the Gym is Self-Punishment in my mind.
But... I don't see how this should make you loose weight really.
It's great for strengthening your mid-section I'm sure, and a lot of people could use that, but due to my back-problems I've basically, naturally developed a set of really strong abs. They're just neatly tucked away underneath an inch or two of bellyfat (and loose skin).
So yeah, you can have awesome abs, but flab on top, so... why would this device, designed to give awesome abs, remove the flab?