I'm not into drama and character development, or long, elaborate social development stories. I'm much more interested in the new tech, the scientific breakthrough, or just a good action tale in a sci-fi setting that couldn't possibly be told in any other setting.
Unfortunately for me, Mr. Bear takes a long time setting up and developing his characters and the socio-political background for his Mars colony. If that's your cuppa, you'll probably love it.
If, like me, that just doesn't interest you, read the first section to get the characters and the background, then skip to the middle of the book like I did. That's about where the science of the story starts to develop, and there's nothing in the part I skipped that I couldn't figure out on the fly.
Even then, though, it was still a little slow and plodding, until the very end when all of sudden everything's happening now, and it's "Go, go, GO!" The ending was well-explained and set up, but Bear spent a long time telling why they had to do thing A, and then suddenly, admittedly forced by their opponents, they had to do thing B. It worked, I think, but it still felt forced, so it didn't work well.
I like Greg Bear's writing, but this one just didn't do much for me. A shame, though, because I loved the scientific breakthrough.