Pretty awesome. Not quite perfect, but I found the ending very satisfying so 5 stars anyhow. 
 Also, I just finished it. I might have a more review-like opinion once I've had more time to process it. 
 OK, glancing at other reviews, I feel like addressing two common complaints. 
 One: The book does a lot of 'telling', it's distancing, etc. The structure is choppy. 
 I understood part of the point of this right away: the whole book is a flashback after an event that takes place near the end. And the structure itself-- well, I loved it. Definitely choppy, but choppy like some of my favorite poetry, skillfully melding emotional resonances. 
 Two: Weak characterization/development of the protagonist. 
 All I can say here is that I strongly, strongly identified with her attempt to understand and learn more about her dead mother. Maybe it's because I have a dead mother, too, and at one point I started to learn that who she was to me wasn't who she was to everybody else, and I kind of ran away from the opportunity. 
 Also, the ongoing themes of motherhood and being shaped by your past and driven by love for your mother, and of standing in the shadow of those who came before all really worked for me. So there's that.