Mehhhh. Compared to Stalin or Mao, Castro was a piker. The Black Book of Communism estimates that through the late 1990s the number of Cubans executed were a mere 15,000-17,000, with another 100,000 Cubans imprisoned - and possibly not surviving. That said, Cuba's population is only on the order of 10M, so Castro had less than a tenth of the opportunity Stalin and Mao had.