I just purchased a Naniwa 12k, and I'm super excited to try it. Should arrive today or tomorrow. I have always used film to keep my straights sharp, and I have been pleased with the result. I did get a little tired of honing on film as it ended up taking me quite some time each session. I usually used a progression of three or four different grades of film then CroOx. With the Nani, I am thinking I will just use it and hone more frequently. I've heard it said that just a dozen or so laps on a 12k will last you several weeks. Any thoughts or tips would be appreciated!