My local knife shop made a video in which they test various Naniwa stones (Work, Super and Chosera) as well as their own water stones.
I like the video, since they actually show how sharp knifes are after sharpening on particular stones. The video is in Dutch, but since they show everything, that shouldn’t be a major problem.
And the video is not too biased. They actually show why Chosera stones are better than their own stones.
It is on http://www.knivesandtools.nl/nl/ct/vergelijking-test-slijpstenen-eden-quality-naniwa.htm . Scroll down 1/3 of the page.