The Emperor's Soul won a Hugo. After reading it, I understand why. Admittedly, I haven't read much of Brandon Sanderson's work yet, but compared to others in the genre he's in the highest of classes. I'll give my score upfront: 97%.
Shai is clever. She's good at what she does. She thinks ahead. She's proactive. She's almost everything you could possibly want in a protagonist. The cast of secondary characters have progressively lower strength based upon how important they are. It's not a fault in the writing. In fact, it may have been done on purpose. The more the character was focused upon within Shai's POV, the more we were able to learn about them, leading to an increase in how strong they seemed as characters. Everything worked splendidly.
I don't want to give too much away about the setting. I have no complaints. The story's set in a faraway part of the world from Elantris. The setting is more anthropomorphic than most.
I had concerns with the plot coming in. I worried for nothing. Everything flowed. Nothing felt too extraneous. There were some cool little subplots that had both aesthetic effects on the setting and tweaks on characters. They were nice to read. The main plot held me. I can't say anything more without giving things away.
Sanderson did pretty much everything right. The only things I can really complain about are the switching of viewpoints for tiny periods of time at the end, although those are forgiven, and the oddity of the chapter titles. They made practical sense, yet were slightly awkward to read.