The organised working class had no role in the Cuban revolution. Consequently, power never passed into the hands of the working class but to a new ruling bureaucracy. It was Stalinist in practise - nationalisations and a planned economy but without accountability to the working class, and repression of critics from the left who, whilst defending the gains made, called for a further revolution to put power into the hands of the Cuban working class. That isn't to dismiss the gains made for the working class in Cuba but neither does it make the Cuban bureaucracy a working class government and it certainly wasn't/isn't socialism. Guevara acknowledged himself that the 26th July Movement and the bureaucracy it created contained many bourgeois elements, yet condemned those calling for a genuine workers' government and/or a w/c revolution. He was a guerrilla, an elitist, who believed cadre could transform society in place of the working class, not that the role of cadre is to provide direction to the working class, engaged in class struggle or carrying through a revolution (which incidentally is where the usual and horrifically simple anarchist critique of vanguardism falls down, by assuming vangaurdism equals the former).
I don't know why some of the critics of Che focus on the killing and slaying and blood in an abstract sense - he killed people therefore must have been a monster. Which is liberal bollocks. Overthrowing a ruling class is inevitably going to involve a wee bit of blood-letting. It wasn't that he killed, or ordered others to kill. It was that he regarded many working class militants as no different to the defenders of Batista and capitalism, as the enemies of the Cuban revolution. His long-held position of placing his revolutionary elite in the role of the working class in practise. It was who he repressed and why he repressed them, not that repression took place.
The repressive, bureaucratic and unaccountable nature of the Cuban government - or regime, or new ruling class - was not a later degeneration, it was the inevitable result of the approach and analysis of the 26th July Movement.
I'm v hungover so this is a bit clumsily expressed but you get my points hopefully.
And I do own a very nice Che ashtray somebody got me from Cuba. It's ace.