Batman vs. Superman: Dawn of Justice didn't have a tie-in novelization, but Suicide Squad does, written by Marv Wolfman, of Teen Titans and Crsis On Infinite Earths fame. I was impressed with his prose writing ability - I'm going to check out his novelization of Arkham Knight - and observed that it's probably (judging from the mixed reviews..or tomatoes, frankly) a smoother experience than the film, which I saw two months after reading the prose. In the past, I've tried reading other novels by comic book writers and found that only Dennis O'Neill, Devin Grayson and Alan Grant had a knack for it, whereas others felt very amateurish. If I didn't own the trade paperback of Crisis, I would've tracked down Wolfman's novelization of it, just to see how he wrote it up.
The book contains fewer Ben Affleck cameos. In it's place, the character of June Moon/The Enchantress and her storyarc in the film is elaborated on by Wolfman. In the film, June's relationship with Rick Flag, her initial transformation into the Enchantress and her enlistment to the Squad by Amanda Waller is just exposition, but it's dramatised in the book and takes up most of the first 1/3...having said that, the final battle between Enchantress and the Squad is really weak.
And I didn't enjoy reading the stuff with the EA's...the tar monsters (my description...or what I gathered that they looked like). All those descriptions of combat fighting felt like Resident Evil stuff. That was not interesting to read. I also disliked all the back-and-forth TV cop show-style bickering between Deadshot and Flag. Audiences liked Will Smith as Deadshot, so I'm assuming his performance added something missing from what reads like well-worn material. Captain Boomerang was fun to read, though the joke about why he owns the pink unicorn doll isn't in the book.
Neither the book or the film do anything with Katana, who's just along for the ride. Whatever additional scenes featuring Jared Leto that might exist on the cuttingfloor don't make it into the book, so it's hard to gauge whether even more material was shot after the book went to press...after all, the novel does have fewer Batffleck cameos...and no Flash cameo, either!
So..how do I sum this up? It has a lot of cool moments. The book does some heavy lifting with the characterization in parts, I didn't really like the plot, because it just becomes a video game along the middle, then has a really weak finale, while the casting choices impose a better movie exists along it's periphery...am I the only one who would prefer to see the newly branded DC Films ditch their labyrinthine plans for Justice League movies and just give us straight up a Batman vs. Joker & Harley Quin trilogy, instead?
Oh, and a trilogy Wonder Woman movies. Everyone loves Gal Godat. :)