I actually took the time to download it and read a while ago. It's not great. It's written by Ed majors, using Ed major jargon, which makes it vague and hard to read. Since it was too big to read altogether, I concentrated on the high school mathematics section. It wasn't bad. It wasn't as good as the high school math I had many years ago, but it wasn't all bad. For instance, Common Core called for plane geometry up to the proving of some lesser theorem. When I took plane geometry, we proved the Pythagoras theorem, which is harder, and basic.
Actually, as far as educating children goes, we would do better by simply requiring all high school students take chemistry, physics, and biology, as well as algebra, plane geometry, and trigonometry.
Anyhow, I am not going to take Common Core as a serious political issue. It's a wedge issue, all emotion, no real substance.