So, No. 1: This book is not targeted to me, it's targeted to people 30-some years younger than me. I read it because it's a retelling of Jane Austen"s PERSUASION (which I love) and I wanted to see how the writer made it work. And she does make it work. Elliot takes more action than the Anne Elliot of PERSUASION, and puts up with less grief from her relations. The writing is evocative and enjoyable, the settings and set-up clear and thought-provoking. I'm sad but not surprised that one basis of PERSUASION, that Anne is persuaded not to marry the man of her choice, was not included in this retelling. Nobody persuades Elliott she shouldn't be with her childhood friend, so she makes no mistake (following others' advice or family pride instead of her own mind/heart) that she later shows she's learned from.
Narratively, it has some things that (to me, an old fart) are drawbacks: a LOT of exposition, repeted and repeated again backstory, characters who are far wiser than their 14-18 years might suggest. The letters between the estranged couple were fun and added depth to our understanding of them, since (YA rule?) we didn't get to be in anyone's POV but the heroine's. I was surprised that they were out of year-sequence, and I did a lot of adding and subtracting whenever I got to one of the letters sections.
For me, the biggest drawback was Kai, Elliot's friend until he is her not-friend. He doesn't seem to have any empathy; if it wasn't for the evil Baron, Kai might be the most selfish person in the book. But he saves girls who fall down and invents cool things, so...
I will recommend it to my nieces, when they hit middlle school--actually, I'll probably give them my hardcover copy. (The cover is gorgeous.) And who knows, they might want to read the source story after that.