This one may actually have implications for us: It is in many ways parallel to Romer v. Evans, where the Supreme Court threw out Colorado's constitutional amendment that invalidated all city ordinances and foreclosed any future state laws to recognize gay partnerships, without amending the constitution again. Then, SCOTUS said, in an opinion by Kennedy, that a public referendum cannot impose an extra burden on one group (like, having the constitution changed) that it does not on another, to pass a law etc.
The Michigan case is in many ways very similar: it imposes an extra burden on African Americans to seek preferential treatment, which it does not impose on others, like alumni, athletes who can't read and write, or residents of the Upper Peninsula.
I haven't read all the opinions and dissents yet - virtually every justice had his or her own take on this, but on the face of it I'm a but surprised that Kennedy didn't stick by his guns from the Romer case. I don't know if that means anything for us in the upcoming battle when the state bans on gay marriages come up. It might warrant a close reading of his opinion today, though. *Can't quite will myself to do it yet...*