For those who had the misfortune to suffer the consquences of his folly, he is not controversial at all. He is a conceited man-child with very bad manners. There's readily accessible, amble evidence for that by looking at photos of him in various settings, both formal and relaxed. The way he dresses and, more importantly, his body language make it quite plain. His writings and interviews attest to the same. BTW, and to do him full justice, his mathy book on game theory is not bad (though hardly a classic) so he may be somewhat competent as an academic economist.