Money will make people do crazy things. I think he's shown time and time again in his handling of situations that he's been pretty ineffective and his primary strategy is to say "we're sorry we have to do better". It's lots of excuses, that's not good leadership material in my book.
There's also crazy stories like the time he gave a speech proclaiming "Carthago delenda est", casting Facebook as Rome and Google as Carthage. Then everyone went into lockdown over the weekend so they could dig through Google+ and copy whatever they could. According to the same book (Chaos Monkeys), Zuck's inner circle is basically a bunch of sycophants (aka Friend of Zuck). It also repeatedly refers to Facebook as a cult. Why do you think they had major failures like the most recent one? Sycophancy is not a working strategy.
Surely he's made some great choices (Instagram acquisition), but how can you begin to separate his actual ability with the power/wealth he can bestow on anyone, biasing their view of him? The guy could fail 1,000 times over at this point and still be a billionaire.
https://www.washingtonpost.com/graphics/2018/business/facebo...
https://www.theguardian.com/technology/2017/jun/16/facebook-...
The stuff that happens there is kind of comical. Would effective leaders really run an org like that?