I did find parts of the beginning somewhere between a bit slow and a bit depressing. Brin is setting up a near future world, with risen sea levels and some people living by finding drowned useful material while others have specs with many layers of overlay, so as you walk down the street you can see labels with information about anything you look at - buildings, people, goods in shops and so on. Virtual graffiti is also common. The story is multi-threaded following rich and poor, an astronaut, an up and coming journalist and a novelist. The information is put over in various ways and I liked the sort of magazine article/blog/radio programme inserts that were two or three page chapters - it was a clever way of informing the reader and added breadth and colour to the world. Due to the multi-threaded complexity of the story, the book does take a while to get properly set up and to get going, but there comes a moment when I literally sat upright, hit by a certain plot point.
The extent of Brin's imagination is fantastic, the world is built very consistently and really hangs together with great depth and there is an interesting variety of people across the different plot threads. The ending is very clever and not one I saw coming.
I read the Uplift series many years ago and have been meaning to re-read for a while. I could see some foreshadowing of the Uplift in this book and am now heading straight to read the Uplift books as I want to do that while this one is fresh in my mind.