Having read the insides working under Latham, I'd say he would have been better. He was rather thoughtful, and more honest. That maturity you mention for me is simply his disagremant with a system that demands people be less than honest in power, and unfortunate idea.

I do suggest you read it. Remember that while he could have selectively edited it to convey himself in a better light, the media has ultimately been responsible for controlling your views regarding him, and this book. When in doubt, read the book. Its not all sour grapes, and its not all rosy pictures of him.