The first thing to know about this book is that it is the sequel to, or rather: the other half of, Lord of the White Hell Book One. That one ended rather abruptly in the middle of a night, this one starts with breakfast next morning. So if you know you liked, or are going to like, the first, you want to order this book straight away. The second thing to know is that this is not the middle book of a trilogy, but the conclusion of the story. At the end, all plots are revealed. The fantasy is elaborate enough to allow the author to revisit the world or even the characters in a future sequel if she likes, but there are no cliffhangers that would necessitate it. The third thing to know is that the story of both books has nothing at all to do with the author's exciting previous book Wicked Gentlemen. In fact, they are quite different: that was a romantic mystery thriller told from the viewpoints of two very weird adult characters, this is rather standard young adult fantasy told from the viewpoint of Kiram, a 17y old first year student at a royal academy.
The book (meaning now both halfs) is a pageturner. I finished it in two days. The characters draw you in, the world building is rich and detailed (culture, religion, cities, family, friends) and you are going to miss it all when you're finished reading. I think the book might have improved by switching viewpoints now and then (as in "Wicked Gentlemen"), e.g. it would have been nice to witness first hand Javier's impressions of Kiram's home in the Haldiim section of the port town of Anacleto, but alas, the "camera" remains steadily on Kiram's shoulder. There are a few misgivings in dramatical development, like when Kiram receives a letter from his academy tutor that potentially shatters all previous preconceptions he, the "genius mechanist", like the reader, might have had about himself, but it's all part of a slippery slope of events that doesn't give you the time to reflect and makes it easy to overlook. Some characters are crooked, but noone, with exception of the antagonist and a loose former acquaintance of Kiram, makes really bad choices that last, and that - together with the "academy" setting -, gives the book a little bit of Harry Potter feeling. No dear character dies.
The book has been compared to Mercedes Lackey's Vanyel trilogy (starting with Magic's Pawn), and related Amazon recommendations include Lynn Flewelling's Nightrunner series (starting with Luck in the Shadows) and Kirby Crow's Scarlet trilogy. Now I think Mercedes Lackey's tearfilled romances stem from a very different period and now feel quite outdated, and Kirby Crow's trilogy is so badly plotted and so lacking in terms of character that a comparison seems insulting - not all fantasy books with m/m characters compare. But liking it to Flewelling's first two Nightrunner books is also what came to my mind when reading the book: quick paced, strong characters, rich world, a litte less drama and horror, more mature sexual encounters. So if you liked the Flewelling books, I think you should not miss this one.