I really enjoyed, this book (indeed all three in the set) and I'm glad to see it has returned to print, since I personally believe it is one of Vance's greatest accomplishments.
It makes for a really refreshing change to see a book which is supposedly to be based on medieval European roots of myth and legend, to actually maintain the spirit and story of the ancient folklore. So often these days, I feel like I'm reading about medieval worlds which were based on series of other bestselling novels. Elves seem so often based on Tolkien's inventions rather than Germanic myth, little people are based on Victorian fairy tales and Enid Blyton rather than faerie tales, which were believed in, in times long past. So often, even when myth and folklore really are used as a source, there is no imagination in the utilisation of the spirit of those stories.
In Lyonesse we have so many interesting characters and places and despite the fact that most really are only lightly touched upon, you get the feeling each one has a story of their own to tell. The central plot is elegant in its simplicity, in the same way that such classic tales as Snow White or Cinderella are, yet it doesn't sacrifice creativity or fall into a cliche to do this.
I heartily recommend this as a book for all lovers of the fantasy genre.