I have never used anything but Arkansas whetstones from soft through extra hard. They have always put a hair splitten edge on any knife, which was made of a material and heat treated so that it could attain such sharpness. Are the diamond hones really better, if not why do you use them?

ASS_CLOWN

Diamond is quick and will cut anything but for the finest sharpening I now use a ceramic stone.Rough it on diamond finish on ceramic. I also use ceramic for serious sharpening of woodworking chisels, planer blades and gravers.

Japanese Waterstones are superior to both. The more friable abrasives cut faster and cleaner allowing less effort to acheive a superior edge. Also using water for lubricant is far less messy than oil. They are available in finer grades than are generally available in diamond or arkansas stones. Their only real disadvantage is that the stones must be flattened more often. Situations where a complex stone shape is crucial is the only place I would prefer ceramics or others to the waterstones. I've extensively used arkansas, india, diamond and ceramic stones as well as the water-stones and to me it's not close, the waterstones are far superior.....DJ