This review will contain spoilers regarding the previous book, Transformers: Exodus, as well as the related Transformers Prime television show.
Transformers: Exiles picks up shortly after the end of Exodus, with the Autobots onboard the Ark on the run from the Decepticon warship, the Nemesis. Planet Cybertron has more or less gone into a coma after millions of years of war, forcing the still battling factions to take to the stars. Exiles was supposed to cover the same story as the video games War for Cybertron and Fall of Cybertron, but author Alex Irvine pretty much rewrote the story in his own image instead. If you have played those games and not read Exodus, you may be a little lost picking up Exiles.
As a series, Transformers is no stranger to continuity errors and a gratuitous amount of retconning. Like the previous book, Exiles feels rushed. We have the Autobots and Decepticons flying across the galaxy discovering lost civilizations who are involved in battles and other conflicts of their own in a single book. It makes planet-wide conflicts feel like small skirmishes.
The book also goes into the history of the original Transformers, the Thirteen Primes, and their artifacts. But this is, to a degree, a moot point. Over the course of the book Optimus finds pieces of an artifact that seems to be the Star Saber, the sword used by the leader of the Thirteen. But anyone who watched Transformers Prime knows that will not be the case, because the Star Saber shows up there. Characterization is not very good either (also like in Exodus). Characters are given practically no physical description and most of them are stereotypical. Autobots act heroic while Decepticons act like maniacs, except for major characters like Megatron and Optimus. It makes most of the dialogue seem very plain.
Following suit from Exodus, there are several errors in the book as well. At one point, Optimus mentions ejecting the AllSpark from Cybertron so Megatron could not infect it with Dark Energon. But back in Exodus, Optimus ejected it before Megatron had any Dark Energon. At another point, a spaceship magically appears out of nowhere after a flying Transformer had transported the characters previously. Overall this books rates the same as Exodus, which is not really a good thing. Exiles tries to do too much too fast and needs some editing, but does add a few important bits to the lore of the series. For a genuinely good Transformers read, stick to the comics.