In my opinion, the Specialty 1K works fine. I normally work on a dozen razors at a time and this stone never fails to do a reliable and consistent job on setting bevels. I normally clean it with a Trend 300 plate after the dozen razors are done. It is a resin bound stone though so it feels softer than it's magnesium bound brother the Professional 1K which is my preference because of the little firmer feeling it gives me on bevel setting. In terms of speed so to speak, I find little difference. Both are good cutters without the abrasive qualities of a stone like the Norton 1K. I think the reason I have liked Naniwa Selective's over all is that that softer feeling provides wonderful feedback when honing razors along with them being so effective. YMMV as always.
Have fun.