Two stars for me means "I pushed through and finished it."
I haven't read any David Brin before, so all I knew was that he existed and that he had a series of books in his Uplift universe, which this wasn't part of.
This feels like a book in two parts: the first three quarters, full of detailed worldbuilding and a great deal of prose that turned out to be irrelevant, and the last quarter, featuring main characters that were only part of the ensemble cast in the first part, and a nemesis which was only mentioned in the barest of ways until then. I estimate that of that first three quarters, two thirds of it could have been safely edited out to make a lean 440-page novel with a coherent message.
Stylistically, Brin is pretty mediocre at writing women, so it's fortunate that there aren't many in this book. …