Rafael Trujillo was a dictator who ruled the Dominican Republic for 31 years until he was assassinated in 1961.
On the bad side, Trujillo was a brutal dictator. He ran a secret police apparatus that ensured that there could be no real opposition to his rule.
On the good side, Trujillo's regime did preside over a time of increased prosperity in the Dominican Republic. His government undertook public works projects that improved the ports, roads, and other infrastructure. The middle class in the country grew.
Now, there's nothing to say that these things might not have happened if he had ruled less brutally. But at least those are positive developments.