Such a weird, touching, beautiful and, sometimes, heartbreaking story. I'll say that I understand the 1 et 2 stars reviews: yes, there's a lot going on here; yes, the point of views changes often, sometimes paragraph from paragraph; yes, the characters may appear to some to not get that much development; and yes, maybe if you're not a musician, some stuff might fly over your head.
I agree that it's not a book for everyone. But for me, it worked. It touched me in a way that I know that I don't want to read it again. But I'm happy to have read it.