I like parts of this book a lot more than the whole. The plot and structure of the book is fairly engaging, and it takes unique turns at times. But the actual writing isn't that impressive.
Jace is presented as an underdog that would be sympathized with, but the more I read about him the more I realized that Jace is really kind of a shitty person. He is presented as someone who has trained and worked hard everyday under his mother's guidance in harsh conditions. Working on being honorable and strong in intense poverty and classism. But then, he gets to school and immediately begins to steal and lie about what he can do? And it is framed as a necessity that he steals from his sponsor, but what was his plan? His mom and him trained him his entire life, but they didn't think of what would happen once he actually got into the school? It's not like he was caught off guard by his hollow core. So. That left a bad taste in my mouth.
Jace also is supposed to be a calculating and intelligent character who skirts the rules - which isn't necessarily a bad thing. However, it makes the idea of him training constantly and diligently seem like a contradiction. If he works so hard, why does he cheat, and if he is a cheater and only focused on bending the rules, why would he work on his training with his mother so diligently?
Then the characters... While there are interesting roles that characters could play, most of them are all one dimensional. The honest kid is honest. The quirky kid is quirky. The show offs like to... show off. It's not very engaging when his friends all have a single personality trait. The most developed character might be Hahen the rodent slave who teaches him to use the cores of rats. And that was probably the most interesting and 'earned' progress Jace makes. But considering that we don't spend enough time with any of the peripheral characters, is not a good payoff.
This is especially true with the villains. The school director has so much free time to harass a single student. It feels childish, especially when the adult director tells the students to pick on this one kid from the slums. Like wtf? How is that even a situation? Could you imagine your school principal making a big announcement over lunch that everyone should pick on a random kid in rags? And this guy is supposed to be one of the oldest and strongest mages in the world.
Another element of this story is that literally, everyone is out to get Jace. Everyone. No one likes him except 3 random kids who he met before his fight that got him into the school. And even they don't stick by him. In the most casual and unemotional exchange, they all basically tell him that they can't be friends bc he's hated by everyone. The principal Grayson hates him. His clan hates him. The teachers hate him. Tyco hates him but is using him. His peers hate him. At this point I'm surprised his mom didn't hate him. I think I was supposed to pity him, but honestly I kinda hate him too. He's a cheating kid who only thinks about his honor and himself.
The other part of this is the writing. It is very straightforward. The author basically just tells you when and what you should be feeling at any given time. When the author wants you to be sad, he says Jace is sad. When Jace feels happy, then we should feel happy. Instead of nuance and subtle actions that display the tone and thoughts of the characters, the reader is directly told. And it's in a very matter-of-fact way. An example is with the sentencing chapter, arguably the part of the book where Jace should be at his lowest point where his hope of restoring honor is broken. This is the part where he almost died, lost all connection to his only family, will be seen as a cheater and dishonorable person and most likely labeled a criminal. And what emotionally charged description do we get? "Grayson was trying to get under my skin, and it was working." That's it. There's no description of fear or unease or tension. It sounds like someone rattling off a grocery list. The writing style is very much that: a style. I personally didn't like it, but others might find it a non-issue.
I think the main story components and ideas presented are intriguing. I like the idea of a Hollow Core and how that limits and aids someone in this world. I even like the political backdrop and rivalries that are going on. But I don't feel engaged by the characters or invested. The bad guys are bad. The scared mom is scared. There's little depth to the characters and Jace isn't a compelling main character.