In many ways, this is a perfectly decent sword-and-castle type fantasy, and in one way it's better, because it has griffins. The griffins are the best part, because griffins are awesome and underused.
The plot is great: we have three different peoples, the griffins, the humans of Feierabriand and the humans of Casmantium, all of whom are arguing over more or less the same terrain. As with many fantasy novels, the people are rather modern and civilized in that they all desire as little blood-shed as possible and are willing to use diplomacy to get it. This was my first hurdle. The characters are all very nice to each other. Sure, they have battle scenes, but when they're not battling, they're mostly civil. They don't have that callous contempt for others (especially low-class people) that one would expect in a medieval milieu. For example, at one point a fifteen-year-old girl falls in with enemy soldiers, and everyone takes it as a given that her safety and her honor will remain intact. Not that I'm fond of violence and rape, but their decorum felt out of place in a military camp.
My other gripe was with the magic. The griffins are creatures of fire, and they create desert to live in by their special magic. This desert is hot all the time, unlike most deserts, which are very cold in winter and at night (unless they are at the equator). I don't know why I'm able to swallow magical sentient flying griffins, and yet get my feathers ruffled when authors play fast and loose with meterology and terrain, but there you have it. I wanted a real desert, like the one I live in, or like one I've visited, and it's not like that at all. This desert isn't a real landscape, just the idea of a desert, a mere symbol. Here's a quote.
"The desert was as cleanly and elegantly beautiful an any airy palace or many-towered citadel built by men, Bertaud thought. But it was not a place meant for men, or for any creature of earth."
(Deserts are not meant for men? Um, tell that to the Navajo and the Bedouins.)
The premise of the magic is that griffins are creatures of fire and air, and are thus inimical to humans, which are creatures of earth. Kes, the main character, becomes a fire mage, which means she can heal griffins and do enormous feats of magic, all of which come at little cost. Not zero cost, we learn that she will "become a creature totally of fire and not of earth" but this is so poetical that I had no idea what it meant. What does it mean to have fire in your blood? To have bones of red sand?
I really like my fantasy grounded in reality. I want to know where Kes sleeps when she's in the desert, what she eats, what she drinks when she gets thirsty (only the dead do not thirst), and if it bothers her that her clothes are dirty or if she's used to that. She doesn't eat anything until about 200 pages in, and then she doesn't eat very much. Having people with no earthly needs makes me think of them as dreamers, and if the story is just a dream, that its outcome doesn't mean that much to me. Neumeier lapsed into florid prose when describing how beautiful and glorious the griffins were, and about the red sands of the desert, etc. but without description of the mud and squalor to counterpoint it, the descriptions just felt like trite poetry.
As for characters, we have Betraud, advisor to Iaor, the king of Feierabriand, and Kes, the girl who lives with the griffins and heals them. Kes did not interest me, as her personality felt too passive and malleable; she occasionally threw a tantrum when the plot required it, but mostly she just did what people asked of her. She has power, but it comes too easily, and she doesn't really seem to want anything, except for her friends not to die. Bertraud had a lot more potential. He loves his king, but he comes to admire and respect the griffins too, and he finds himself caught between them. I think I could have found his story quite engaging, if the novel hadn't been bogged down with unnecessary description, ungrounded descriptive prose, and explanations of a magic which felt at its core to be based on flawed premises. (Everyone knows that the opposite of fire is water, not earth.) I wanted a horse-and-castle fantasy in which plausible griffins were folded into the ecology, and instead I got a fable with fairy-tale physics.