This question has too wide a scope for me to effectively answer it in one go. Instead, I'll give you a good introductory book recommendation and link/excerpt a bunch of posts I've done on socialist Cuba. As you've said, Cuba is very polarizing and it certainly isn't black and white. The Cuban Revolution was very popular and brought a dramatic increase in the quality of life and social inclusion of the large majority of the Cuban people and acted as perhaps the most active force against imperialism and colonialism in Latin American and Africa. However, the Cuban state also practiced significant political repression and, though it has since reversed this position, repression against homosexual men. It was completely unlike any other state in the region and I would argue that its revolution was among the most important in history.

If you're interested enough in the topic to read a fairly short text, I would recommend A History of the Cuban Revolution by Aviva Chomsky. While we might typically think of the "Cuban Revolution" as the military conflict that lasted from 1953-1959, in this case it means the decades that followed in which the Cuban state tried to revolutionize society, moving from a capitalist model to a socialist one. It doesn't go very deep into every issue, but it's a good overview of Cuba's successes and failures.

My user profile in the subreddit wiki lists some of the larger answers I've given to questions here. I'll link some and provide excerpts from the "Cuba & Che Guevara" section below.

Why did Cuba go with the Soviet Union?

The United States took a hostile approach to the Cuban Revolution following the May 1959 agrarian reform program, crafted by Guevara, which restricted the size of private farms in Cuba to 3,333 acres. Cuba had not yet declared its revolution socialist or Marxist-Leninist, and the U.S. ambassador stated that Fidel Castro had no interest in international communism at the time. The United States, after consulting with large U.S. landholders, launched a covert war "to bring about the replacement of the Castro regime," by bombing Cuba and its sugar plantations. After the bombings, Cuba nationalized U.S. landholdings and corporations, and the U.S. responded with the famously botched Bay of Pigs invasion. After this, the 26th of July Movement (the revolutionary organization) merged with the Popular Socialist Party, eventually declaring a Marxist-Leninist program and becoming the Communist Party of Cuba.

What happened to Cuban culture following the revolution?

Culturally, the Cuban Revolution represented a commitment to democratize the arts, as an extension of Che Guevara's goal of the "New Man" of Socialism. While I cannot speak to the quality of art and culture before and after the Revolution, it is clear that after the Revolution, all corners of society were engaged in ways like never before. Cuba's world famous literacy brigades were accompanied by artistic workshops. Rural workers would come home from the fields in the evenings, learn to read for the first time in their lives, and hold workshops in which they would paint and produce other art, previously the domain of an upper sector of society. The goal was to "decolonize art".

The Cuban Electoral System

The "Candidacy Commissions" choose the candidates to be voted on during the National Assembly elections. The commissions are made up of elected representatives from organizations representing urban workers, farmers, students, women, and young people, on the idea that candidates should be chosen with the interests of every sector of society in mind. There is then an election, in which people vote "Yes" or "No" on the candidate. If a candidate receives less than 50% "Yes" votes, the process begins anew, but that doesn't really happen. For what reasons, you can draw your own conclusions. It could be because the commissions do a good job of representing people's views, or it could be because people don't want to go against the state.

Was it the truth behind the critical controversy surrounding Che Guevara? Was Che a murderer, a homophobe, and racist who needs to be viewed much more critically?

Following the triumph of the Cuban Revolution in 1959, Guevara was assigned for a time to oversee the prison at La Cabaña. His duties involved overseeing the executions of those convicted of war crimes at the prison. Because of this duty, Guevara is sometimes called the "Butcher of La Cabaña" in the Cuban ex-pat community. The revolutionary government claimed to be basing its trials for war crimes upon the international precedent set by the Nuremberg Trials. The process consisted of two tribunals, one of which tried civilians and one of which tried members of Batista's military. Only the latter could order an execution for those convicted of war crimes. Guevara's role, like that of governors in the United States, consisted of reviewing the verdicts, offering pardons, and setting execution dates. Guevara remained assigned to this role for several months, during which he oversaw between 55 and 105 executions.

Was Che Guevara a successful and proficient military commander?

I would say that Ernesto "Che" Guevara was a proficient commander of guerrilla warfare. Much of the success of the Cuban Revolution can be attributed to his revolutionary strategies, though this must be reconciled with his failure, capture, and execution in Bolivia. The success of a revolutionary is not measured in conventional terms, and Guevara himself stressed that revolution was only possible under specific criteria.

Was Guevara a successful government leader?

Perhaps no one was more responsible for the sweeping land reform of the revolution. As Minister of Industries, Guevara raised an agrarian reform militia of some 100,000 Cubans, which he directed in seizing land to be distributed among workers' cooperatives. Serving as both the intellectual and physical force behind Cuba's escalating land reform programs, Guevara was responsible for drastically changing the nature of Cuban society. Agrarian reform had been a promise he had extracted from Fidel Castro during the revolution, and his influence in the sweeping program that followed ultimately led Castro to declare the Revolution to be socialist.

As the effective head of the Cuban economy, at one point being Minister of Industries, Finance Minister, and head of the National Bank, Guevara sought not only to stabilize the country's economic situation, but to transform the very nature of humanity. He held that socialism could only be successful with the creation of the New Man. I've just turned up a quotation from a historian that characterizes this ideal as "selfless and cooperative, obedient and hard working, gender-blind, incorruptible, non-materialistic, and anti-imperialist." I would suggest reading Guevara's Socialism and Man in Cuba to come to a better understanding of this doctrine. On Guevara's days off of work in his ministries, he labored as a construction worker and sugar harvester, and the image of Guevara cutting sugar cane in the fields is still used to motivate Cuban workers. Not everyone was so committed as Che, however, and productivity dropped in many industries following the elimination of material incentives in favor of moral incentives. Though Guevara would explain this as the failure of those just beginning the transformation of the New Man, explaining that those born and socialized into such values would perform better under the system, it is seen as perhaps the greatest failure of Guevara as a leader in Cuban government. It was somewhat mitigated by Guevara's role in securing beneficial trade deals with several Eastern Bloc countries.

I don't have the space to excerpt the full answers in all of those links, but you should look through them if you're interested. For example, the first and last links both speak to Cuba's medical and literacy programs, which are widely considered to be the greatest successes of the Revolution.

Feel free to ask any specific questions. I'm not an expert on Cuba, so there's a lot I don't know, but I've studied it historically and have enough background to offer some insight.