J.
My son has a November birthday, and cousins very close in age who will be a year ahead of him in school. I hate the idea of paying for another year of preschool, and he's a pretty outgoing, bright little guy - it does seem like kind of a waste.
But I wouldn't push him ahead anyway. The NYT article is a good read. Also, my older son is a July birthday and one of the youngest in his class. You can pretty much line up the kids by age to pick out the best readers and the ones with the most social skills. My son is bright, but he is nearly a year younger than his best friend in the same grade, and it shows - he tends to lag behind a few months in things like when they were moving to chapter books. It makes my son feel like he's not quite smart enough, when a lot of it is developmental advantages because of age (my son is at or above grade-level, but the fall birthday kids were 7 for the whole school year, and my son isn't 7 yet and school is out! If you think about it, they've been alive 1/6 longer than he has - big difference when you've only been talking in sentences for 3 years!)
It's not just academics, either - it's social skills, everything. My advice - let him enjoy the natural advantage of being a leader by just going along with the state cutoff of Sept. 1.
(I meant to add - if you read the article, you'll see that states with 12/1 cutoffs are thinking about changing those cutoffs, including Michigan.)