It seems most people either passionately loved this book, or passionately hated it...personally, I'm on the fence. Also I did not read Twilight, which this is supposed to originally be fanfic of, so I'm unsure if that has to do with my thoughts.
Honestly, the writing was quite bad. The author really liked to make the characters murmur and mutter and whisper a lot - there are much better words out there. In many places, the writing was juvenile, the character of Ana was VERY immature (also the name Anastasia seems like one a 12-year old would pick...everyone else in the book has sensible names and then there's Anastasia), and there were several places where nonsensical things were repeated (ie: "The Kate Kavanaugh Inquisition", and Ana's "inner goddess"). It seems like something written by a very young teenager when it comes to much of the plot. And to top it off, in order to make the writing seem better, she used "big" words that nobody uses (ever) instead of common words in places (ie: castigate instead of chastise).
The only redeeming part is the passionate scenes, and because they are so well written is why I'm on the fence. So what I've come to determine is the author really knows how to write a sex scene and then tried to make the storyline fit and hasn't quite figured that part out yet.
And so, as much as I disliked the writing, I'm hoping the next 2 books are better, as I have bought all 3 in the trilogy, and therefore need to read the rest.