Hi
I always try to use as much categories as possible, at least until my mind blows with the time spent and the extra work.
I guess this is not as important as they make it dificult to insert one image, as people in general are used to search by keywords. At least the buyers I know all of them told me they use mostly keywords on the search box and not so many category search.
But people think diferently and what's true and good for a some friends of mine could be wrong to some others.
I guess if they make the process easier, it will be great for us photographers but also for the reviewers.