A solid 3.5, tentatively upgraded to 4 (because I really did actually like it).
The comparisons to Valdemar are inevitable, but I don't think this book suffers. The main characters (comparing first book to first book) are rather different in nature, and that permeates the rest of the story. Here we have a young heroine who is much less naive, a little older and much more self-assured. Karigan suffers little in the way of the crises of self-confidence that Talia of Valdemar does, It's also rather nice for once to see a heroine from a stable happy and firmly middle class (for this world at least) family environment, rather than an unwanted foundling or th (I have a pet peeve about that, actually. I call it Bob. It hogs all the cat food too, so I'd like to see it go away. Not every hero/ine has to be shaped under a horrible upbringing, it's satisfying indeed to read about someone fairly ordinary being put to the steel and tested by circumstance.)
As a first novel, there's a lot of world building, but little flat out exposition for exposition's sake. Some of the characters are truly intriguing and I will be looking out for them in future books, although Karigan herself could have been a little more fleshed out - but then, as a teenage girl, she's not quite fully formed yet, so maybe she couldn't be. But the world is internally consistent, and makes sense, it feels like there's more to it that we haven't seen yet, but we've learnt enough to follow along.
Really not too much more to say, she's up there with Paksennarion of The Deed of Paksenarrion and indeed Talia of Arrows of the Queen as pretty good (s)heros for YA readers, especially the horse mad early teen kind. She doesn't spend her time pining for the prince, indeed, there's little romance in the book at all, which is refreshing, and maybe reflects that it's a little older than the current crop of instalove sparkly rainbow time books of the last few years.
As an adult reader, it was a fast read, indeed a lazy Sunday afternoon spent on the sofa with some good music playing, and I knocked it off in one sitting. Which is far from a bad thing, sometimes you want a light salad, not a big meaty steak. And anyway, it's the first of a (now four part) trilogy, and I will definitely be getting hold of the others. And for once, I think my teenager and I will agree on this one.