Here's what a few critics have to say about the work of Le Guin:

Robert Scholes:

In the Land of Oz, all the good witches come from the North and south, the wicked witches from the eat and west. But we do not live in the Land of Oz and must take our witches as we find them. Ursula Kroeber Le Guin, born in California and a resident of Oregon, is very much of the west, and the literary magic she works is so dazzling as to make the title of “good witch” almost literally appropriate.

Criticism "The Good Witch of the West," found in Modern Critical Views: Ursula Le Guin

Susan Wood:

It is evident, then, that Ursula K. Le Guin’s work possesses a thematic and conceptual interdependence consistent with her philosophy. Discussion of any one element, or any one novel, quickly leads to a branching network of cross-references and examples. Nevertheless, within the overall pattern, each work explores a unique aspect of the human problem of right living, on and in response to a unique world.

Criticism: "Fiction of Ursula K. Le Guin", found in Modern Critical Views: Ursula Le Guin

Douglas Barbour, about The Word For World is Forest:

Le Guin’s fictions are all imbued with great sympathy for the strange “human” cultures they present. Nevertheless, the Athshean culture of “Forest” is her clearest example yet of a culture presented as in basic and violent conflict with present-day “Earth-normal” standards but still as unequivocally the saner of the two.

Criticism: "Wholeness and Balance in the Hainish Novels of Ursula K. Le Guin", found in Science Fiction Studies (Spring 1974)