Because No Contest was assigned reading for my Social Problems class, I read it differently than I would have if I just picked it up. We were required to write a 3-5 page essay discussing a specific aspect of the book or a general thesis of Kohn's that we would then agree or disagree with. This meant that I was looking for something to babble on about - but something I could babble interestedly about.
Part of what Kohn says is that competitive sports and games are actually less fun than non-competitive sports and games, and the reason is that all motivation becomes extrinsic. You play to win. In cooperative games, the point of playing is the pleasure of playing - not a reward at the end. I thought this was Kohn's most well-supported claim, and the most interesting one. Some of the other chapters were cluttered and overly academic, which made them hard to get through. But I think the book is worth taking a look at.