There is an excellent piece by Paul Berman on Slate, here. To give you a flavour:
"The cult of Ernesto Che Guevara is an episode in the moral callousness of our time. Che was a totalitarian. He achieved nothing but disaster. Many of the early leaders of the Cuban revolution favored a democratic or democratic-socialist direction for the new Cuba. But Che was a mainstay of the hardline pro-Soviet faction, and his faction won. Che presided over the Cuban revolution's first firing squads."