This book was discovered by me a few weeks ago and i decided to check it out. Before i tell you of my experience reading it, it might help those Arrowverse theorist nuts to know exactly where it takes place in the timeline.
Arrow - Season 4 (after Green Arrow)
Legends of Tomorrow - Season 1 (Before Pilot, Part 1)
Supergirl - Season 1 (before Worlds Finest)
So yeah the book itself was pretty impressive. It really showed our heroes accurately. Team Arrow and Team Flash. However it even did some things that the show had not done before. Allowing character interactions that we never usually see on screen. One of my favourites was between Joe and John. They really had similar motivations for fighting crime. A couple of other interesting relationships come from the Rogues. They are the villains of the book, but the true main villain is the Rogue's leader the Pied Piper. This guy is bad news on so many levels because he has a mind that can outsmart his former co-workers at S.T.A.R labs, and he has a power that can have him stand toe to toe with Oliver and Barry. The rogues teaming up is done so good with the personalities of Rainbow Raider, the Mist, Weather Wizard and Peek-A-Boo really clashing off one another. Plus if you wanted to see their iconic bickering go on, you get plenty. Oliver is really only there around two thirds into the book, but he definetly gives a new perspective that is needed when you spent 240 pages with Barry and friends. Oliver has a more brutal style with taking out enemies. (even innocent victims of Rainbow Raider's rage.) Which can be good or bad depending on your moral standards. Iris also has more of a bigger role than she usually does. Being able to get info from criminal gangsters and even metas that worked with the Rogues. Not as much references to comic book material this time around however Barry experiences visions of his allies and enemies. These visions include Future Flash, (who, in this version is much older and looks like the 1990's TV show version of the Flash) Multiplex, Firestorm, (Ronnie) Grodd, Zoom, and finally Eobard Thawne himself. This book has alot of what makes the Flash great.
However there is some negatives that i am going to touch on. The book doesn't really touch on certain characters and i find it a little suspicous. Jay Garrick/Hunter Zolomon is only shown as Zoom in Barry's vision. We never actually get to see him even though he is a member of Team Flash. Who knows though, he might be dead at this point. However one character in the show was consistently alive and is not in the book. That man is Dr. Harrison Wells. They also never mention the team's Earth Two adventures which is very strange. Black Canary and Speedy also don't guest star with the rest of Team Arrow, but that is more excusable because they got to defend Star City while Oliver is away. It is just a glaring thing that bugged me. Another is the fact that Oliver doesn't remember the pipeline and Cisco doesn't remember Oliver's Lian Yu A.R.G.U.S prison.
The following is a rant on the story of the book.
So in the story, Barry is hallucinating in these events called "blurs." They drain his speed and are caused by his emotions. S.T.A.R labs eventually figure out that the reason this is happening is because of the wormwhole above Central City seen in the finale of S1. Some plasma from the wormwhole has made it into Barry's system. (It is attracted to the Speed Force so it didn't affect Martin Stein) The team is completely clueless and decides to not Vibe Barry's visions even though Caitlin said it would make it easier to stop the plasma. They literally forgot Cisco's power in this. I know that Arrow writers helped on this book and not Flash writers but still. Speaking of that, Felicity ended up being the one that tells them where to save Barry. That would lead into the next Arrow book where we get a new Count Vertigo!