I quite like that it doesn't really have much to do with the overarching plot. My main gripe is that a lot of the assassins didn't particularly act like assassins.
The reveals about the truth of Mars and the Mechanicum were the best bits. The titan battles I could take or leave. The main character's journey was interesting but she was frustratingly idiotic (for a genius).
The Solar War 8/10
Enthralling non-stop action (and I'm not usually keen on the battle based books), with a fantastic reveal at the end which we should have seem coming!