This is an excellent series! I really had trouble putting the books down!
First, Mr. Brin must be praised for creating a truly unique universe for both UPLIFT trilogies. The very premise of the structure of Galactic civilization is completely different from anything other authors have done.
Unlike the first trilogy, the second trilogy is much more cohesive and I would strongly advise that the books be read in order.
The first book of the second trilogy, BRIGHTNESS REEF, starts off a bit slowly because Mr. Brin has so much set-up to do. After you slog through the first 50 pages, then things start to crackle. Mr. Brin tells his story as a series of interwoven tales with different heroes at the heart of each. This constant skipping from one tale to another kept me interested, but it also got a bit tedious to the point where I was almost tempted to split the book apart and read the different vignettes as separate stories.
My only criticism is that Mr. Brin can get a bit hokey at times, like his E-space dimension (in HEAVEN'S REACH, the third book of this new trilogy) where imagination and reality intermingle. The concept of a universe shaped by the imagination of the viewer is a tired and very trite idea that has been over-used in SciFi.
Also, there are a number of background details that Mr. Brin doesn't get into in either trilogy, so I would recommend CONTACTING ALIENS as an adjunct to this series. A lot of things make more sense with the help of this "guide to the Uplift universe."
In the end, though, Mr. Brin tells a spellbinding story and writes a very enjoyable series. Well done, Mr. Brin!