Cons: It's not really a standalone. You'll want to know more and the cliffhanger at the end is primo.
Pros: Everything else. Characters are great and evolve, world seems consistent, the reasons magic doesn't solve everything feel right, the
El (Short for Galadriel, like, you know, "All shall love me and despair!”) is an outcast and a hard worker. Her mom is a kind hippy wizard who sees her differently than the rest of the world, which is to say her mom loves her and doesn't think she is a force of darkness destined to be an evil supervillain. She works hard to do things ONLY in the good ways so she never sets a foot on the path of darkness, no matter how many people she desires to invert over an ant-pile in the course of a day.
We meet El inside the Scholomance, a superdark high school for teen wizards. In this world, magical monsters LOVE the taste of young wizards and consume them like junk food. The Scholomance was founded to give young wizards a better shot at growing up by teaching them in a place where only 60% of them would die instead of the 80% that were munched in the outside.
Graduation day in this school is a horrific race to escape the school while a sea of monsters scoop up as many kids as they can.
In this brutal world everyone is in constant danger and looking for an edge for survival. It's set up as a zero sum game - everyone knows that most of the people around them in freshman year will be dead before they leave. You are looking for any advantage possible to keep you in the fraction of kids that make it out. The class inequalities outside the walls are of course reflected inside and we get to learn about how it all works through El's eyes as she struggles to not alienate the powerful despite her instincts - if she can be in with the powerful kids, she stands a chance of making it out the doors. Of course the powerful exploit their advantages as well and demand anything that will help tip their odds.
But every single chance she's given she finds herself turning away from. Even when she attracts the attention of Orion Lake, the nearly invulnerable wizard in her class with an talent for slaying monsters far beyond his years. Yes, yes, yes of course, but the journey is a good one.
The end is a triumph as characters discover hidden talents, strengths, connections and the power of working WITH each other instead of trying to get an advantage over each other. And the final sentence sets you up for a hell of a ride in the next book.