I finally sprang for one these gizmos and it's a cleverly engineered little device. I had been eyeing the thing for awhile and just as a number of others here I was dubious about the value. I'm still dubious. I doubt that it would be terribly complicated or time consuming to construct a similar jig that would accomplish the same thing. But having received a bit more of a tax refund than expected, I splurged. My first disappointment was when I opened the box and discovered that the GRR ripper required assembling. It would probably have cost the company another 10 cents per unit to have a Chinese laborer assemble the gadget but for the asking price........... Maybe a patent search was expensive. Maybe the engineer was very well paid. Maybe they don't sell enough of the thingies to appreciate volume pricing. Whatever, I expect to use it in good health. ;-)
Max