Well, here you have it from the horse's mouth...well, the horse's brother's mouth.
In a speech Raul gave yesterday in Brazil, he let us all in on what he believes to be the Revolution's greatest accomplishment.
I'm sure the suspense is killing you, so here it is: Resistance.
"We resisted, I think that is the greatest accomplishment of our people, our greatest accomplishment; we resisted and we are here."
"Resistimos, creo que es el mérito mayor de nuestro pueblo, el mérito mayor nuestro; resistimos y estamos aquí..."
I mean really, so many things that he could've pointed to: healthcare, education, the international spread of revolution, etc with the typical responses.
But this is very telling. For Raul, the greatest thing to be accomplished is ideological resistance and existence.