Blues, ahh, I see!
I didn't even think about that aspect of it.
bgentry, I was disappointed with the XXC, as well as other stones around 120 grit, didn't remove metal as fast as I thought they would . But I often use 120 for sharpening, so the money was still well-spent. I agree with you about the positive aspects of diamonds and usually finish with the DMT C.
Patience when removing knife metal isn't one of my strong points. Although I like diamond plates, I've found, over time, that I can hog off metal freehand the fastest using coarse, low grit, SiC, where I can use considerably more pressure than diamonds. The Manticore is the best I've found, and is the only stone I now use for this purpose.