Prince Andrew is about the worst of the bunch. There have been allegations of corruption and sexual misconduct.
It was revealed in the United States diplomatic cables leak that the Duke had been reported on by Tatiana Gfoeller, the United States Ambassador to Kyrgyzstan, discussing bribery in Kyrgyzstan and the investigation into the Al-Yamamah arms deal.
Earlier in 2010, it was revealed that the Kazakhstan President's billionaire son-in-law Timur Kulibayev paid the Duke of York's representatives £15 million – £3 million over the asking price – via offshore companies, for the Duke's Surrey mansion, Sunninghill Park
In May 2016, a fresh controversy broke out when the Daily Mail alleged that the Duke had brokered a deal to assist a Greek and Swiss consortium secure a £385 million contract to build water and sewerage networks in two of Kazakhstan's largest cities, while working as British trade envoy, and had stood to gain a £4 million payment in commission
In March 2011, it was reported on the Duke's friendship with Jeffrey Epstein, a convicted paedophile. Sarah, Duchess of York, disclosed that the Duke helped arrange for Epstein to pay off some of her debts. The Duke strolled publicly with Epstein after the latter's release from prison, allegedly while negotiating this financial help
As of November 2014, the Duke had met Ilham Aliyev, the president of Azerbaijan, on 12 separate occasions. He had to stand down as a trade envoy for the UK in 2011 following controversy over his friendship with Aliyev, who has been criticised for corruption and for abuses of human rights by Amnesty International, but he has continued to visit him in Azerbaijan since standing down
The prince has consistently used his position to promote arms sales and boost some of the most unpleasant governments in the world, his arms sales haven’t just given military support to corrupt and repressive regimes. They've lent those regimes political and international legitimacy
So Andrew wins in this race by a mile.