I picked a Gransfors puck with my recent purchase for 40 bucks. It seems like a handy, portable tool-although I am yet to need it. Recently, I saw a Norton sharpening stone at Home Depot for less than 10 bucks (larger rectangular). I didn't mind paying for the Gransfors steel, but the stone now seems way overpriced. Does anyone have any experience with the Norton stones? It was so affordable, I may have to get one and save the puck for travel use.