Not guilty here. I'm the cheapest guy in the county, and I live in an impoverished county. lol
I actually bought the same thing as the Kamui tool, but with a plastic mounting board and no fancy wooden case held together by rare earth magnets. Cost me less than $15 from some 3-cushion guys at SBE this spring. Looks and works the same as the Kamui. I'd provide a link but I can't find them on the net.
Tiger also makes a similar tool, but it has two grades of plates on it, plus two shaping depressions for either dime or quarter tip, all on a rugged anodized aluminum plate - no useless wooden case - for the same price as the Kamui one. I'm gonna pick one up and give it a try.
FWIW these things have been around for a while before Kamui came along. Rodney Morris showed me his and he said he's had it for many years and it still works great, so it won't wear out like a $30 piece of chalk. I saw several other pros at the recent Turning Stone with the same tool as Rodney has. The laser cut pattern looks to be identical to the Kamui pattern, but the actual plate is smaller in size. I'm sure many pros know the whole story about how long they've been around.
They don't work the same as sandpaper at all, and hardly remove any leather from the tip if used correctly. Tip longevity is real economy to me, plus less aggravation getting used to new tips. I use mine more like a tip conditioner than a shaper. You roll it over the tip surface and the pattern pulls up just enough nap on the tip to help the chalk go on. Here's a pic of the UltraSkin soft I put on when they first came out. The shape has been maintained entirely with the Kamui-type tool since last April, and as you can see, there is very little wear in that time, and the Blue Diamond sticks to the surface real nice as well. I like it a lot, and would gladly pay $30 if I had to. I'm a full-time woodworker, and I have hundreds of dollars worth of abrasive papers of every sort in stock. I'd pick this tool over sandpaper in a heartbeat.