At first I liked the idea of including both sisters' voices in the book. It made for a nice structure, with Ruby blurting out the present while Rose plodding unveiled the past, and if Ruby hadn't been there to throw in some excitement, I think I would have left the book unfinished. But having finished it, I think I would have enjoyed it more if Ruby's contributions had been left out altogether.
Rose is bogged down by trying to be a proper writer, and I found her musing about tone, theme, and narrative structure clogged up the story and pushed me away emotionally. I wanted to know about her life as a person, not how hard it is to write a book. Being reminded how hard it is while reading the finished product was annoying to me. Novels about the writing process are too self-referrential for me, it's like being able to see a microphone in the scene of a movie. On top of that, I found I liked Ruby's story-telling better, and almost wished it was her diary I was reading, not Rose's autobiography. Going back and forth only seemed to highlight their faults – Rose, too guarded and self-conscious to be interesting, Ruby, too amateur and disinterested to be satisfying.
I kept reading because I wanted to find out what was going to happen, which turned out to be not much at all. I don't think the characters changed much during the novel, and it certainly wasn't plot-driven. The prose wasn't anything special. But, although I wished it was better, I still liked it.