Patricia McKillip's greatest strength is her ability to produce dreamy but compelling language - almost invariably about characters searching for a vague but romantic sense of place or self. Usually, the search takes place in a traditional fantasy landscape, where magic is often mentioned but seldom seen. In Kingfisher, she steps away from that with a faux-modern setting, complete with cars, and dishwashers, but also mysterious powers, similar to what we've seen in some of her recent short stories. The magic remains mostly allusive and mysterious.
The setting worked very nicely, though it took a while to realize exactly what world McKillip was using. Where the novel has less success is in its deeply allegorical theme, replete with references to Arthurian legend, and all set against a backdrop of Christian religion.
In my view, McKillip does best when she's focused on one character, trying to make sense of the world based only on scraps and fog. Here, there are simply too many characters, all connected, and not enough actual plot. The Christian elements only weakened the story for me. While they're not directly alluded to, they're hard to miss, including in the book's title, Kingfisher. While the book plays with religion in general, it's hard to escape the implication that Christianity is what really matters.
McKillip hasn't lost any of her writing skill, but I found this novel unsatisfying. While the prose is as good as always, the plot is murky rather than mystical, and the allegory heavy-handed rather than delicate. A passable book, but not up to the usual McKillip standard.