All around excellent book! I was sucked in by the unique color coded class system (Golds rule, Obsidians are soldiers, Reds mostly mine and live out their lives deep underground) but what really hooked me was Darrow's character development. The world building is superb, from the early chapters detailing day in the life of a Red spending their life underground never seeing the stars to the depiction of Golds and how they are shaped into future leaders...it's all so compelling.
If you enjoyed the Hunger Games, you've got elements of the series in here ranging from killing to bonding with others thrown into the same deadly situation. You've got the political intrigue of Game Of Thrones and even a tad bit of Harry Potter in terms of school houses and the bonds built and broken between members of them.
Come for the cool spin on dystopia worldbuilding, stay for the well developed characters and unpredictable plot twists..some violent, some anything but violent.
I know your time is limited, so just know this book will NOT waste your time. It's well paced, well written, and I think it's my new favorite book of all time