I have a translucent that I have used on only a couple of edges. I have yet to work with the black one I have as a finisher as I am of the impression that it is either of the same or lesser grit that the translucent. I could be wrong, though, as I have yet to use it.

I wouldn't use the translucent all by itself as a finisher. It took me hundreds of laps to get the edge I wanted off of it coming off of a dragon's tongue. I have used it on an edge finished with a shapton 12k pro, and it took much less laps. It did take away from the sharpness a little, but made the edge much smoother. Not as smooth as a coticle would have left it, but still much less harsh than the shapton. I would say it is somewhere around 10k in grit and very slow. If the black one is similar to the translucent, then you could probably use it to maintain an edge, but it would take more laps than a barbers hone.