Transformers: Exodus novel takes place in the same continuity as the television show Transformers Prime and the video games War for Cybertron and Fall of Cybertron. The following review makes a bit more sense for readers familiar with those things.
Part of the Aligned continuity family, Transformers: Exodus covers the same events as the War for Cybertron and Fall of Cybertron video games. Or at least proclaims to. Many details both small and large were changed for this story, from the way certain events happened to the origins of characters and outcomes of major events. For the “official history” of the Transformers civil war, it was certainly lacking.
Exodus starts out at an earlier point in time than War for Cybertron, showing Megatron’s gradual rise to power and the time he and Optimus spent as allies rather than enemies. Transformers is a multi-verse with various continuity families, but Exodus is specifically designed to meld with Transformers Prime and related materials. Yet, it does not. There are scores of differences between Exodus and War for Cybertron, such as the point of Starscream’s defection to the Autobots and the creation of Megatron’s warship.
Along with the differences, the book is also loaded with errors. For example, at one point Optimus seems to teleport between two cities on different parts of the planet, twice, within a span of six pages during a single conversation. The major outlying issue with everything that happens once the war gets started is that War for Cybertron and Fall of Cyberton told this same story but did it better. This war is supposed to have lasted for millions of years but Exodus does not leave that impression on readers. Bad descriptions do not stop at events either; virtually none of the characters are physically described so hopefully you already know what they all look like.
It would be a stretch to say that the book is all bad, but it is hard to see much good in it. This was as bad for Transformers books as Michael Bay was for the movies. With Transformers Prime being considered the high point of the television show by many fans, it kind of stinks that this serves as its official prequel. Exodus works fine as an outline but should not have been a standalone novel. Far too much of this story was cut out in a franchise that has had 25+ years to build itself up.