The first half felt quite slow—probably because of all the "training" parts, which are always hard in terms of balance to achieve (too little, and it seems too easy and unbelievable; too much, and it starts to drag). The second part was better, more exciting.
New characters are introduced here. We get to learn more about Aedion, and to meet Rowan, who fortunately seems to be taking the road of "loyal friend" rather than "love interest" (love triangles are already hard for me, so more sides to the polygon just means more trouble). On the other hand, less screen time for Dorian and Chaol, and sometimes I felt that their POV chapters were here as reminders they still existed.
I think the one character I definitely liked and wanted to know more about was Manon. (It's like the Dragonriders of Pern, but evil! Yay!) She was determined, focused, a no-bullshit woman, and with more to her than shown at first, considering her relationship with Abraxos. Celaena... I don't know. She's growing as a character, yet also going away further from the "assassin" trope, and I'm still of a mind that had she been a warrior/mercenary, it would just have achieved the same thing. We'll see in the next book, I suppose.