This is the third Star Trek novel I've read by these authors in recent months. I made excuses for their Enterprise book given the series had just started, but after reading this, I will be wary to pick up anything by them again. Shadow is supposed to be set towards the end of the fifth season, and indeed was written after the series had finished (or at least close to the end of its run), and yet I felt not a single character was portrayed accurately.
Section 31's role in this is practically zero, indeed, the agent isn't even on board Voyager for any of this tale, instead being loosely linked in with a season 4 episode. The scheme employed by the agent isn't particularly original either, when you consider Seska's holodeck assassination attempt in season 3.
Janeway, without any real warning, decided she doesn't trust the crew, except for the three crewmembers who have probably been taken over, brainwashed, or tried to mutiny the most times out of anyone.
Seven apparently only has two settings. Irritated and hostile. But according to the authors, she finds her the irritation of being irritated irritating (repetition is a failing of these authors that's annoyed me before). Also, she says things in this book that just didn't happen in the show - I never recall her calling anyone by their first name, least of all B'Elanna.
The Doctor is in season 1 setting here, when he was snappy and rude, not the more sedate and compassionate Doctor in Equinox.
Tom makes weak jokes, or worries, Torres has a complete disregard for the Rhawnians, mainly because they're purple (hmmm). Only Harry and Chakotay are accurately portrayed, in that they rarely speak.
The B story of Lyspa and Andra is actually pretty pointless in the whole scheme of things, and could've been left out without affecting the story. In fact, the idea that they'd build one massive ship for 800 million people, rather than a convoy of escape ships actually defies logic.
Voyager itself causes concern as well. Season 5 introduced the Malon, who hadn't managed (or wanted to) learn how to dispose of harmful by-products of warp drive. Voyager is proud of the fact they mastered it, and want to share it. Yet this book makes mention of toxic trilithium resin tanks, the evil exhaust of warp cores (given that trilithium only seemed to be discovered shortly before Voyager was launched, this is unlikely), and also we have the semi-sentient computer, which apparently has enough consciousness to target specific crewmen.
All in all, this book, and the authors, seemed (again) to change or distort established facts in order to propel their story along, and in the end, it served to affect my enjoyment of the book. Easily the weakest in the Section 31 series, certainly not a patch on the DS9 entry. I'd probably recommend you to avoid this one.