I had no idea what to expect when I went into Ninefox Gambit, and it was extraordinarily confusing for the first... 100 pages or so. The book begins in media res during a big future/magic infantry battle except the magic might be high-level mathematics? In the first 20 pages alone are going to be puzzling your way through deliberately alien concepts like "calendrical rot" and "linearizable force multiplier formations" and "threshold winnowers". These aren't presented a friendly, "here's a new word, we will explain it now, or at least provide some context way." They are presented as things everyone takes for granted, and if you're lucky, in the next 20 or 50 pages you will gather enough contextual knowledge to piece together what they actually mean in the world of the book.
That could all be a really bad thing, but ultimately it ended up being kind of like a fun puzzle.
Ninefox Gambit (and the following two books in the Machineries of Empire trilogy) ultimately pays off all the weird math/magic stuff. It ends up being an extremely powerful metaphor for the systems that underlay all imperial powers. It's kind of like LeGuin's "The Ones Who Walk Away From Omelas", but writ large as a space opera. I give this book four stars, though I would give the series as a whole five? The series as a whole is greater than the sum of its parts, and I like the first book more in retrospect having read the next two books in the series.