Meh.
I bought this becuase I'm always looking for a good, white pen or marker and I'd read a review saying this was the best the reviewer had ever used. It's ok, but it's not white on dark paper. It soaks in and looks gray. I prefer the inkadinkadoo or gelly roll pens. They are narrower but whiter. Devotees of Holtz will probably LOVE this though, since it has his name on it. :)