Written in 1992, Throy is one of Jack Vance's last novels, followed by Night Lamp (1994), Ports of Call (1998), and Lurulu (2004). Along with the Throy's immediate prequel Ecce and Old Earth (1991), I consider these books Vance's late works. All of them are very similar; all of them exhibit Vance's characteristic style, humor, and creativity. And yet there is something missing. Sadly, all of them are a bit slow, consisting of long sequences of loosely related adventures on various worlds, something captured in the title "Ports of Call". By comparison to his tight novels and short stories of the classic years, these stories feel a little flabby, even indulgent. Which is fine because more Vance is a good thing.
Some of my favorite bands continue to produce new albums long past their heydays: McCartney, Townshend, the Stones, Sting. Perhaps John Mayall is the best example. It is hard to point to any diminishment in the quality of their songs. In terms of technique and craft, they are arguably better now than when they were young. And yet, I go back always to their earlier albums, and it those songs which drew the bulk of their audiences. So it is with these late Vance books. Read them, savor them, but don't be surprised if your primary response is to be reminded of his earlier classics.
Notice that I did not include Araminta Station, the first book in the trilogy ending with Throy, in late Vance. That one is notably better than its sequels, and despite its length is a quick, highly engaging read, and of my favorites. The only flaw with that book is that is not standalone and the sequels do not live up to it.