Locked-In has two main elements that are both strengths and weaknesses.
The first is that John Scalzi has put quite a bit of detail into the back story of his scenario: a disease has ravaged the world and left vast swathes of the population locked into their own bodies, but with technological advances that also let them communicate online and through robot bodies. It’s good because you never feel that sort of hand-wavy pseudo-science of, say, a second rate scifi movie, but on the other hand, with all the scaffolding in plain view, it seems like a very coincidental set of circumstances to arrive at the same sort of scenario as one of those movies (sort of telepathy! robot bodies!).
The second is the plot itself, a murder mystery set in this new world and featuring a detective (a new FBI agent) who is himself a victim of this disease. Scalzi is good at nerd-friendly heroes who are very clever and achieve clever victories over their foes, which can be very satisfying to a puzzle-solving brain (like, indeed, my own). But again, there sometimes seems something just a little pat about the ending like the one this book has.
FuzzyCo grade: A-