Since no one else is willing to talk about his actual character traits, or do much besides give political speeches, I'll give a few of my own opinions.
He was from the time he was young a strong-willed and headstrong man, certain of the correctness of his ideas and mission. It is probably true that in the beginning he genuinely wanted the best for his country, and was possessed of a burning desire to right the wrongs he saw all around him. Make no mistake: Cuba under his predecessors was little more than a huge plantation, exploited at will by corrupt elites and foreign powers.
He would pursue those ideas single-mindedly for decades, even after all available evidence suggested that changing course would produce better results.
His success and survival owed more to the ineptitude of his enemies than it did to the soundness of his ideas or the brilliance of his plans. Communism was never embraced by more than a small minority of intellectuals, and if the Cuban people knew what he had in store for them, they would have lynched him the moment he arrived in Havana in 1959.
But if he was a dour fanatic, his enemies to the north played right into his hands by refusing to leave him alone, imposing one pointless embargo on him after another, and turning his island into little more than a hacienda for the use of himself and his cronies. In that respect, one can look up on the Castro era as something akin to the old proverb: "Evil against evil." Meaning that both he and his enemies deserved each other.
As time went on and isolation took its toll, he retreated more and more into dictatorial fantasies and self-aggrandizing delusion. Like Dionysius of Syracuse, a notorious tyrant of antiquity who was also lord of a small island, he found validation in his own longevity, thinking that it conferred on him legitimacy. It did not.
His appearance on the world scene and freakish survival owes more to accident than to his own abilities. Islands and peninsulas are notoriously easy to dominate for long periods. On balance, and taking the long term view, it would have been better had he never even been born. Cuba's economic developments under his rule would probably have occurred even without communism--look at Guatemala, the Dominican Republic, and Colombia today compared to what they were in 1950--once we consider the incredible work ethic of the Cuban people.
Against this damning indictment, we can possibly say a few positive words, although these do not begin to even the scales from the weight of the negatives already described above. He did provide some sense of national "pride" in the form of "cubanismo"; his social system did, it must be admittted, manage to raise the health and educational standards of the average person, when one looks at the median. But we can't say that this meager positive outweighs the accumulated negatives. Perhaps the final verdict on Castro must wait for another decade, in order to see how quickly the country climbs out of the stagnation his rule has left it in.
On balance, we can say for now that it would have been better had he never been born.
