My main gripe is that it's simply not the splash & go stone it's advertised to be. In fact, without soaking it at least 5 minutes or so it's as if there's a tampon hidden in there that keeps drawing the entire stone dry. You keep splashing water on and it keeps going dry. Then it feels as if you're just rubbing your knife on rock-hard rubber, and the 'slush' just becomes like rubbery crumbs from an eraser.
It gets better when you soak it for a few minutes but it never really becomes what I would describe as 'nice'. Even when it 'works' you never really notice it does. Funny enough the Arashiyama 6k I recently got was a lot nicer to use and worked great without any soaking at all, even though it's a lot cheaper.
Weirdest thing about it is that it's so much worse than the 400 & 1000, which I never had any issues with. Actually quite love the 1000. Same line, completely different stones.