I'll certainly be labeled as a communist in this day and age for going against the military dictartorship presidents, certainly as many people today are not content with the current administration of the country because of corruption scandals and money laundering from most politicians, but there was a lot of censorship in the 60's here in Brazil, every meeting had to be previously reported to the police — even parties. If more than two people started to chat at a corner, at a bar table or wherever, a plainclothes policeman would approach them and tell them to disperse. Police went to parties uninvited if someone invited for it was suspect of anything. People stopped inviting to parties those who had ever had problems with the police or been vocal for the left.
School life went from bad to terrible. Some subjects, like History, Philosophy, Latin, Greek, Literature and French were abolished in 1968. Political doctrination was included as a subject called OSPB (Organização Social e Política do Brasil = Social and Political Organisation of Brazil) and watered-down History and Geography were conflated into "Social Studies". Mathematics and Portuguese were given prevalence. School hours were reduced from eight to four and a half. Trusted people were assigned to every school, they'd wander the corridors hearing what teachers told to the students, they's meet the students in private and ask them to report on the teachers.
Economically speaking, while it's true that Brazil reached the 8th Economy position during the military rule, when the dictatorship was over, Brazil was another country. Most of the population had left the countryside to live in cities and millions of people had migrated to the more populous states, such as São Paulo and Rio. A modern and vigorous industry had become responsible for almost half of the wealth produced by the country. But much of the progress made during the miracle was reversed. In 1990, Brazil's average income had retreated to 20% of the US average. Economically, it was bad. Brazil went through a phase of very big economic growth, but inequality raised a lot and it was a irresponsable growth: it was made borrowing a lot of money creating a public debt so big that today is unpayable. Since that late 70's, the military junta also put Brazil in a very big economic crisis with very high inflation that lasted until the mid 90's. The country had 60 million undernourished Brazilians (whom the government called "Carentes")
And all the money in the country was at 4% of the population.
Because of the hyperinflation, when the Oil Crisis occurred in the 1970s, the house of cards collapsed and revealed that was a false growth, it generated unemployment, de-capitalized the country and entered the 1980s, which became known as the lost decade. Plus the base education in Brazil was extremely poor, which led to many people being functionally illiterate and only taught the basics of math and reading comprehension, something that is also reflected today.
About Itaipu, sure, Without her and many others that were built during the government we could not end our industrial park and Brazil would be doomed to be like an African country, full of misery, hunger, war, death and disgrace. Itaipu has enough energy to host 35 million brazillians, and is the biggest hydroelectric in the world, but just because it was built during a Military Dictatorship, doesn't mean a democractic government couldn't have achieved the same, without sacrificing censorship and freedom of speech, also there was just as much corruption in that time as well, and it was even worse because you could not speak about it, if you spoke even the slightest about the government you'd be imprisoned, even if it was nothing related to socialism/communism.
The good thing about democracy is, the leaders hold office only for a short time and are then subject to the people's judgement of their work (through the election). With a dictatorship, especially a military dictatorship, the people do not have any means to express their desires, or to demand for a change in government or its policies, except through a coup or a civil war.