This happens to be one of those books that is both brilliant and lacking at the same time. I will explain myself. 
 The novel is actually quite as daunting and impressive as Startide Rising and The Uplift War in it's way, but it's mainly because Brin doesn't ever stint on world building. Ever. He goes all out and develops tons of alien races, tons of characters, and a great many implications for the amazingly complex alien culture among the 16 galaxies. 
 Truly, I have nothing bad to say at all about the quality and depth of its development. It's actually rather staggering. Brin never rests on his laurels. He finds new avenues to drill down into and I should say that there are VERY few authors who do it as deep or consistently as he does. 
 So what's lacking? 
 Well that's a very complex creature, too. My primary go-to complaint is in the basic story, but it isn't because it's too simple or too complex. Rather, it's because I was constantly wondering why I should care about some far distant fallow world where a bunch of alien refugees including humans had tossed all their technology into the drink in order to hopefully devolve genetically, culturally, and intellectually. Why would they do it? Because while they're political and cultural dissidents to the rest of the galactic society, they're also adherents to a weird quasi-religious tenant that is diametrically opposed to Uplift in general. 
 They want to return to innocence. 
 (Of course, not everyone believes. Humans are a bit more complex and have their own reasons to buck this trend with their books and their skepticism of the galactic culture that either doesn't want to be bothered to help the upstarts, but that's a sub-plot.) 
 I have no problem with the concept. In fact, if this was any other novel by any other author, I'd be touting it and the way it approaches the subject as honestly unique and fascinating. So what's my problem with it? I don't like book-burning. I'm in love with books. Of course, these guys take it all the way and sink their spaceships and all their tech, too, with a few human exceptions, but the core is the same. 
 What we've got is a novel about aliens and humans interacting in very complex ways with the ever-present fear that the galactics will find them and punish them and their entire RACE for the crimes of despoiling a fallow planet that should have remained fallow and untouched by anyone for several billion more years. That's a steep punishment for a broken law. Notice, too, that the galactic culture with its many, many, many species is an establishment that has been around for a very, very long time. Nothing stays around that long without being a very robust system. Mostly it relies on just out-waiting problems. :) 
 ...Including dissidents who are thinking in terms of devolving themselves to pre-sentience. :) 
 Too bad that plan goes to seed. :) 
 So what's my problem? Too slow, maybe? My expectations wanted more resolution on a huge scale instead of what amounts to a tiny backwater and backward hamlet in the middle of nowhere? 
 Well that's my own damn problem, right? The novel is still a damn sight better than the majority of alien society novels out there by any yardstick. My problem is that I am judging it by his other brilliant Uplift novels instead of just focusing on what it does right. And it does a lot of things very right. 
 Of course, it's also book one of a trilogy that really needs to be read together if you want any sense of closure, too, so there's that. :) 
 And since I've read these before and I know that the end is practically a full 180 degrees from where we start now... I should have just kept faith from the start. :) So I will. I *was* of two minds about doing this re-read, but now that I've done this second read two decades after it was published, I'm now somewhat amazed and chastened that I should have worried. This is still a classic Brin. 
 I just needed to manage my expectations. :)