I bought King of Swords and its sequel, Queen of Stars, without even thinking, just because I like David Duncan. I'm one of the long-term fans he refers to in the dedication. Unfortunately, either Duncan is in a slump recently, or I am. He's been producing a lot of new books, and I've liked very few of them very much.
One of my key gripes about this book is its premise - discontented human goes through portal to a happier world - I've read a lot of books along those lines, and they very rarely work. There's just something about the idea I don't care for. This one is no different.
Part of the problem is that regular humans are slaves in the elfworld (and genetically degenerate enough to deserve it, apparently). Halflings like our hero Rigel don't do much better, but that suits him just fine, because ... I'm not sure. The main thing seems to be a beautiful woman, who he makes it his life's ambition to kiss (that just sounds creepy to me). Duncan doesn't do much to establish the world, and it frankly feels like he's not trying very hard. There's a lot of exposition, but even so, some of the characters' actions are unfounded. It has a facile feel that didn't interest me much. Throughout the book, whenever I put it down, I tended to forget I was reading it. Definitely not one of those books I like awake thinking about, or can't wait to pick up again. By the end, I pretty much didn't care about any of the characters.
Duncan has written much better books in his time; just not lately. This one, unfortunately, is eminently forgettable. Also unfortunate, I have the sequel already.