A collection of stories which focus upon, primarily or via premise, changelings in a more in-depth light. These stories are simply above the curve... sometimes so much so as to be almost iconic in their execution.
Stories which take the idea of transformation (of whatever sort, though often human to pony) and flesh it out in a manner which is enriching, thought provoking, and altogether worth the time investment.
These stories, for lack of a better phrase, are simply worth the time investment. They are thought provoking, deep, well written, and otherwise far above the normal offerings.
Stories that are worth the time to read, but have little standing outside of themselves. Generally brief, but fun for the read or to fill a few minutes.