The Domains of Koryphon is unusual for Vance in containing a fairly explicit political message - in this case about property ownership, conquest, and prior possession. There's also a leavening of Vance's more standard self-reliance, and a more evident than usual criticism of effete urbanites in favor of taciturn, outdoorsy, cowboy types.
That said, there's also the usual Vance inventiveness and language. Erjins and morphotes share land with Uldras, Wind-runners, land-barons, and Outkers. Tragedies and mystery take our protagonists across the planet to encounter weird, beautiful landscapes and strange, unpredictable creatures as we learn surprising things that get to the heart of the planet's history.
Vance cheats a bit in this case, leading us towards a crucial mystery, which is then presented in a strangely understated way. He also withholds key information in order to surprise us with it later. It's not the most satisfying of resolutions, and feels at times a bit pro forma. At the same time, the environment, while not developed to the level of some Vance books, is intriguing and fun to explore.
While most Vance books feel as if the author is exploring right along with us, this one feels like he had a message and created a story to carry it through. Overall, the book is good, but most recommended for established Vance fans.