Trump's I win/you lose mentality is why banks and contractors stopped doing business with him in the U.S. and why he was forced to look globally for new business deals and funding partners. I wouldn't go as far as to call him a crook, but he's applied a great amount of legal pressure to those with whom he has done business to force them to accept less money than was promised. 

In my opinion, he's not a good person or a good leader.