overall point:
There's a few factors to talk about here. Cuba under Castro was unique in a lot of ways, politically and economically but also socially. In some aspects, Cuba under Castro was able to achieve remarkable progress in areas like education and healthcare, and to this day the nation has what is undoubtedly the best healthcare system in Central America in spite of having below-average GDP per capita. It is also important to examine the extent of political repression under Castro, and to put that in the context of the political and social situation in pre-revolution Cuba. Social Progress Let's look at healthcare more specifically, since that is often lauded of communist Cuba's greatest achievements. Just prior to the revolution, Cuba had an infant mortality rate of 60 per 1000 lives, a maternal mortality rate of 125 per 1000 births and a life expectancy of about 65 years. The linked source mentions that by 1988, infant mortality had fallen to 15 per 1000 (compared to the contemporary 9 in the OECD and 22 in the Soviet bloc, and 54 in the rest of the Caribbean), while maternal mortality fell to 77 per 1000 births. Today, Cuban life expectancy is among the highest in the world at around 79.5 years, compared to the UK's 81.2 years and America's 79.3. Furthermore, Cuba has played a big role in medical development, exporting some $120 million worth of drugs in 1995 and being praised even by such conservative sources as The Economist for its medical establishments which "have made breakthroughs in vaccines, immunology and biotechnology"1 . Additionally, Cuba has made outstanding educational progress under Castro. Pre-revolution, it is estimated that a quarter of the nation was illiterate, yet by 1961, only a few years after the revolution, UNESCO had confirmed that basic illiteracy was essentially eradicated from the nation thanks to an intensive educational campaign. Today, the average Cuban citizen can expect to spend 10 years in schooling, compared to roughly 13 for the US and less than 8 in the average Caribbean nation. So, Cuba achieved significant social gains in the decades since the revolution, and significantly, achieved much greater gains in social welfare than other Caribbean nations aligned with the US. But at what cost? Was the political repression worth it?
Political Repression
There's two factors to look at here: what was the political situation like before Castro, and how bad repression under Castro actually was. From 1952 until 1959, the year of the revolution, Cuba was ruled by a military dictatorship under one Fulgencio Batista, who staged a military coup when it was clear he was about to lose the election in 1952. Under his rule, somewhere around 20,000 people were killed by the state2 , while presiding under an economy that was an increasingly unequal and impoverished nation3 . The most critical thing to understand here was that at this time, the Batista regime was supported both by the official US government and by private American interests, which according to President Kennedy, came to "dominate the Cuban economy": At the beginning of 1959 United States companies owned about 40 percent of the Cuban sugar lands—almost all the cattle ranches—90 percent of the mines and mineral concessions—80 percent of the utilities—practically all the oil industry—and supplied two-thirds of Cuba's imports. All this together paints a portrait of pre-revolutionary Cuba at least as repressive as Castro's regime, and more importantly of a repression sponsored by American public and private interests, especially private firms that saw Cuba as a source of cheap profit. Given this situation, the violence and repression of Castro's regime becomes more understandable, if not justifiable (especially in more recent times). Especially early on, repression could be understandable if neighboring superpowers are actively attempting to overthrow your government and assassinate your leaders. Looking at the broader history of the revolutionary government, some scholars estimate that there have been some 15,000 state killings in Cuba since the revolution, only a small minority of which were prisoners lawfully condemned to death by the justice system. Today, Cuba remains the only nation in the Americas rated as "not free" by Freedom House, a largely US-government funded NGO. However, this is ok comparable to it’s past.
Conclusion
So how was daily life under Castro? Especially in more recent times, relatively peaceful (the last execution was carried out in 2003, with no extrajudicial killings on record), and with most repression being limited to the jailing of a few hundred activists. Education and healthcare remain stellar, and other basic indicators of development are decent, currently placing Cuba in 67th place for its Human Development Index. It should be noted that on the overall rankings, this places Cuba above nations like Brazil, Colombia, Jamaica and Belize, but below Panama, the Bahamas and Argentina. Why is the capitalist one excused?
EDIT: I found this point on reddit, but I expanded on it.