Le Guin is an ashtonishingly versatile writer, and this collection of short stories is a good illustration of her wide range. The Compass Rose mixes science fiction with fantasy, alternative history with feminism, and sometimes just knocks you over the head with a good, plain, old-fashioned fairy tale.
Some of these stories don't really come within the realm of 'speculative fiction' at all, and I think it's these that show Le Guin's mastery most clearly. Her characters remain well-rounded even without gadgets and sorcery, the language is precise and the tone often delightfully mischievous.
However, it's the sheer inventiveness that makes me really like The Compass Rose; Le Guin blasts open calcified ways of storytelling and challenges her reader as well.