I have one that I have used a bit. Mine did not come with instructions, and I may just be too stupid to figure it out on my own (yeah, right), but I found it very awkward to use...on plain edges. It works great on serrated blades. It makes an adequate bench stone. It will work well for repairing tips on punches and the like. Just don't ask me to hold the tool steady rocked to the right with my left hand while I hold the knife blade vertical in my right hand and run the right side of the knife edge down the left side of the sharpener, because I am just not that coordinated. And I sure am not coordinated or ambidextrous enough to switch the knife to my left hand and hold the sharpener in my right for every other stroke. I'll stick with freehand on a benchstone for PE.