Certainly not a bad book, but like the narrator describes on her death bed, it's a bit like someone's flipping the pages of a novel though her entire adult life. Every chapter is extremely repetitive. Poe sells a work, is happy. Poe has job, is miserable. Poe quits job, sells no more works, everyone starves. Lather, rinse, repeat. Sometimes they move to a new city to start the cycle over.
The biggest problem with that cycle is it's in no way about Sissy. The book isn't about her, or her hopes and dreams. It's a checklist of events in Eddy's life, marked off as seen though his wife's eyes. In the end, she's just not a very realized character.
*edit* Lowered the score to reflect the plagiarism controversy. I don't know if the author intentionally plagiarizer or not, but I do know that too many passages are similar to be coincidence.