Star Wars: The Force Awakens earlier, but since I'm a die-hard SW fan, I thought I'd give the book a try. Especially since it was written by Alan Dean Foster, who wrote the novels for SW4 (A New Hope), SW5 (The Empire Strikes Back) and the spin-off novel, Splinter of the Mind's Eye. I enjoyed them back in the day, especially Splinter.
So, I paid the price and downloaded the E-book. I hoped the book would flesh out things a movie, of necessity, cannot go into. Lots of whys and back story, merely hinted at in the film. I've tried to avoid spoilers, but there might be some mild ones.
I was immediately disappointed. I didn't like the writing style. It's very much a narrative, with omniscient point of view. As a result, we move from one character's thoughts to another. It's a perfectly valid writing style, but I have become accustomed to, and prefer, deep third, where you get into a character's head and stay there for a time. I write like that, too. Having said that, Tolkien wrote in omniscient, and I read LOTR many, many times with hardly a squirm.
One of the first things I tripped over in the book was the scavenger wheeler-dealer who buys Rey's items when she brings them in. This clearly non-human individual is portayed as a sleeze who lusts after Rey. And I went <sigh> Didn't we get over this stuff in the Fifties? Oh, no we didn't. Leia in the metal bikini and Jabba. Although I suppose a case could be made he was merely humiliating the princess, showing her off to the mixed gathering in his palace. That's not how it comes across in TFA, though.
Next thing was the interrogation area. It seems the new star destroyer doesn't have a detention area. After all, where would an escaped prisoner go. Really? REALLY??
For the rest, the story flows along with the movie script, so lots of description is hardly necessary. I'd seen Rey rappelling down the inside of a shattered star destroyer on the screen. I'd seen the desert, and Captain Phasma. And I learned Finn told a colleague he hadn't fired a shot because his blaster had jammed. That's why the captain wanted him to turn in his weapon.
One thing that worked much better was a description of how the star ripper weapon worked. On the screen we see spirals of energy being sucked from a sun, which had me rolling my eyes. But in the book, the weapon collects dark energy and stores it in an electro-magnetic oscillating field. That was sufficiently plausible techno-babble for me. Although I have no idea how you'd get that across in a movie.
Apart from that I gleaned little from the book that isn't in the film. So my all-round Star Wars 7 experience remains at "meh". Roll on Rogue Squadron and here's hoping Star Wars 8 has a little more to offer.