Well, this book continues being raunchy, dirty, and pornographic. It tells the next part of the story from Christian's perspective. It was entertaining and I tore through it in 8 days - started it January 14th and finished on January 21. I liked it.
Here's what I didn't like. This is the telling of the story in the 2nd 50 Shades book - 50 Shades Darker (hence this book's title just Darker). However, this book departs from the original story it is based on. Things in this book are completely different than in the book it is derived from.
For example, Christian's sub, Leila, does pull a gun on Ana in her apartment, but it happened at a different part in the story than the original, Leila buzzes Ana into the apartment - Ana assumed it was Kate's brother who was there already waiting for her. Kate's brother doesn't make an appearance in the original. When Ana leaves the apartment, in the original she walks alone through a rainy Seattle. In this version, she leaves with Kate's brother and gets drunk. There are many many examples of inconsistencies and flat out different scenarios in Darker than in 50 Shades Darker.
So, while entertaining, and a page turner, this was off-putting. It was basically a different story. Maybe this is intentional - this is supposed to be from Christian's perspective, but most of this book is revisionist history.
If you are a die hard fan of the original, this will likely be off-putting. If you don't care that much, you'll probably like it.
Oh, and reading this, I see even more direct correlations to Twilight.