I was impressed at the level of conflict this play had for characters new and familiar. Harry Potter and the Cursed Child is both a tribute to the orginal series, and the opening act of a new story.
My favorite character was Scorpius who lives under the shadow of Draco Malfoy's connection to the Death Eaters and Voldemort. Scorpius and Albus both live under the shadows of their fathers' pasts, but they respond to that element in very different ways.
Albus rebels and refuses to acknowledge his father as just a person. He sees the celebrity that Harry Potter has become, and he feels he could never live up to the greatness that his father appears to have. His actions, rash and implusive, drive most of the story. Scorpius, on the other hand, has a different perspective. Instead of lashing out at his father, and allowing the cruel words to get to him, Scorpius lives his life the way he wants to. He loves to read, and he has some of the best lines of dialogue in the entire play.
The dynamics of Albus and Scorpius's situation are the core of this play, but Harry Potter's struggle with the past is a powerful story as well.
This book was a duet between Harry's guilt and Albus's anger.
I found as I read this, that I could relate to both sides of the story, and it was interesting how everything came together in the end. It has a powerful message for both generations to relate to, and I think it's a good one.
Without spoiling the story, there were times where the story seemed liked a fanfiction, but given the circumstances, perhaps it wasn't too far off.
And one particular scene will haunt any Harry Potter fan no matter what house you've been sorted into. The symbolism of that scene speaks volumes.
Overall, I'd give this four out of five angry flying books.