All right, let's try to write this thing. I'm still feeling sleep-deprived, so it may not be coherent, but here goes:
This was pretty darn good. Not exceptional, not rocking my socks off, but solid, and interesting, and trying new ideas I'd never quite seen before. And the new ideas are subtle. The writing style is serviceable, but won't set the world on fire any time soon. It was never quite a page-turner, but wasn't hard to pick up either.
MacLeod starts from some interesting base assumptions, and then does some interesting things with them. The book starts in the year 14,000 and change. I was perplexed at this, at the start, as his people don't seem that different from people now, or any extrapolations over the next few hundred years. Why go so far in the future? What was the point?
And then the reason for this started to dawn on me, due to one of the core conceits of the book - that humans had been out there in the stars for so long and had never encountered another race. How long would it take for it to become a core belief that they never would, that they were truly alone in the universe? Hence, I think, the extreme far-future setting.
But then they do, a race of winged bipedal humanoids. The book shifts back and forth between the colonization ship that had been coming to this new system, and the winged people on the planet. Both have their worldviews shaken, both have to start "learning the world" anew. Core concepts are examined, and many of the problems stem from those who don't even realize that the playing board has changed, and try to react as though what they have always known is still true.
On the ship, one young woman, Atomic Discourse Gale, realizes the full extent of the change, and becomes a major force in the debates splitting the ship. On the planet, Darvin and Orro, scientists both, first discover the ship entering the system, and later, with the help of Darvin's squeeze Kwarive, a biologist, discover some of the ways the humans are gathering information on their world.
The world of the winged people is, as far as the people on the ship can perceive, backward in many ways. They live on the brink of an industrial revolution, and keep members of a similar race as slaves. From these facts, the humans act on assumptions based on their own far history. This is a mistake.
First contact stories often depict us being the ones who are right. If we don't intervene, it's from some higher morality that prevents us from imposing our own values on them. This doesn't mean that those values, "our" values, aren't shown to be right, always. The poor deluded saps have to work through their own problems, until they finally grow up enough to be welcomed into our enlightened family.
That is not what we find here, and it's so refreshing. I'd never examined first contact stories (where we're the ones doing the contacting) in that way. Assumptions of a higher morality exist, and are entirely wrong. We all just blundering our way through, and the human way may not even be the best.