Intel CBN VS Diamond wheels
As to CBN or Diamond, it is decided for your application.
Tormek origional is with diamond wheels. I think that is because diamond wheels can be used for multiple application. But if the end user is specially for knife sharpening, better use CBN wheels. Because CBN is softer, when sharpening knives, it has better finishes than diamond. Becasue diamond leaves deeper scratches. Also CBN works better on HSS or hardened steel, most of knives are made of them.