I've only got a collection of 3 waterstones, all Nubatama. The coarse is the Nubatama bamboo 150 grit. The one that's brick colored and very thick. This stone works, and definitely grinds steel sort of fast. But I have several quibbles with it: It's really porous and hard to keep wet, even after some mud is produced. The noise it makes while grinding is loud and off putting. When it's wet, it makes WAY less noise, but as I said, it's very hard to keep it wet. Once it produces mud, I think it grinds faster, but the mud is thick and sticks to the blade, so when I'm trying to evaluate the edge, I have to first clean the mud off, which means extra time and getting my fingers more wet and more dirty more often. Finally, it's sort of fast, but honestly the DMT XXC seems to grind quite a bit faster. So I guess I want a quieter stone that grinds faster, stays wet more easily, and has either thin mud that doesn't stick, or no mud at all. Which seems to point directly to the Shapton GS 120. But that's just my first blush at this and I'm still pretty new to waterstones. Any ideas? Thanks, Brian.