Why the difference in silicone carbide stones?

[NeedItCheaper]

I'm still on my "buy all the sharpening stones..." kick. Recently got Naniwa's Lobster 120/220 silicone carbide (29$) to compare to my Dan's silicone carbide (supposedly 220, feels like 320ish). Naniwa's 120/220 performed significantly better and I'm wondering what in the construction of these stones makes the difference. I've got a Gritomatic on the way just to see if there's a huge difference there too. Stones were tested on Tops Tanimboca & B.O.B. each with 1095 steel. What do you think are the highest quality Silicone Carbide stones, or which have done best for you over the years?

 

[UncleBoots]

I'm no expert, but it's not obvious to me that the difference you're seeing is one of quality.

First, different stone makers might be using different grit scales. Unfortunately, 220 grit does not always mean the same particle size in microns.

Second, the binder makes a huge difference. A stone whose binder is softish and very ready to release fresh grit will sharpen very differently from one with a hard binder, that releases only reluctantly. One might come away with the impression that the soft binder stone is better, because it will be faster. It's not the whole story.