The real test of the Cuban Revolution will be when Fidel retires/dies. Recall that when Stalin died, the first small steps were taken in the Soviet Union that eventually led to the restoration of capitalism. Likewise in China, when Mao died.
The problem is, obviously, the essential frailness of what purports to be "communism" in ANY country where the urban working class is, in fact, a tiny minority of the population. The whole idea of communist revolution was (correctly, in my view) predicated on the assumption that it would ONLY take place in the most advanced capitalist countries.
Trying to get around this leads to major difficulties. A revolution in a predominately agricultural country may certainly employ communist rhetoric; but its real class character does not change so easily, and tends to re-surface when the charasmatic "great leader" passes from the scene.
Stalin and Mao stayed in power long enough to get industrialization well under way (it didn't hurt that their respective countries were large and rich enough to do it). The emergence of openly capitalist economies could have been (and SHOULD have been) predicted.
From a class standpoint, what SHOULD happen in Cuba after Fidel is the more or less rapid restoration of pre-revolutionary conditions; Cuba as a U.S. dependency, the restoration of the great plantations, the emergence of slavish dictator-types like Batista, etc.
Yet, one cannot underestimate the (temporary) effects of "accidents" in history. If a new generation of dedicated communists emerges in Cuba (always a possibility), Cuba might well continue to "hold out". And should it happen that Cuba holds out long enough (another 50 years?), there arises the possibility of a communist revolution where they're "supposed" to happen--England, or France, or Germany. Suddenly Cuba would have a real friend with real clout...and then you could finally say with probable certainty, the Cuban Revolution has been victorious.
My personal feeling is that however things turn out, the Cubans have written a magnificant page in the struggle against capitalist tyranny. Remember, Athens was defeated by Rome--but who is remembered with admiration as the birthplace of freedom and who is despised as the archtype of imperial tyranny?!
