I think I've read about four meters of shelf real estate worth of SF novels.
Each of them was unique in its own ways, and in hindsight, Anderson earned his place on my bookshelf. the world created in "Hidden Empire" is consistent and logical, although no deep scientific explanations are given - e.g. for the Theroc world whose plants are "quantum images of each other" and so allow its inhabitants to instantly communicate over any distance via the plants. Humanity has split up, one part is the Hansa, a group of planets whose business is modelled after the great Hanse empire in the past, the other are the "Roamers" which somewhat resemble a modern version of "space gypsies".
All in all, I liked the world he created.
Anderson starts off a bit slowly, when I started the novel I liked his writing style but the plot line seemed too predictable. I found myself saying "oh come ON, this is *obvious*" when one of the characters was struggling with a decision.
But Anderson got me in the end. About one third through the book, the plot turned away from what I expected. Things got more complex and more interesting and thrilling. And the last dozen pages are so full of action that you just can't read fast enough.
I think Anderson needed some time to "warm up". :-)
I recommend this novel for everybody who likes 'hard' SF - aliens who are not (necessarily) evil or more advanced than humans, lots of cool tech gadgets, many different characters, a bit of politics, corruption, intrigue and sex, and an interesting future for humans.
Everything's in there and it fits well. I found the characters to be believable and likable, even the villains can be understood (except where the reader is lead on a false track on purpose of course). Buy it, enjoy it, and endure the first couple dozen pages, it gets MUCH better then. :-)
Jens