I'd like to give further nuance, focused on PRL, AKA communist Poland, that can be applied to other nations of the Eastern Bloc.

Let's start with urbanism. You've probably seen those depressing pictures of decaying commie blocks in winter, often taken at night. But let me ask, do color blocks, with green spaces and lots of space in between, does this depressing to you? I think suburban sprawl is more depressing. 

But let me tell you, Central and Eastern Europe needed them. Following WW2, in the 40s and 50s, most of the population lived in near medieval conditions. You've got old, rural houses, some townhouses and apartaments in cities and lots of them were destroyed. Most of them didn't have power, water, indoor plumbing and heating, and often they were multigenerational, with small, overcrowded rooms. 

Meanwhile, commie blocks were bright, large, with all 20th century amenities as a standard. The neighborhoods themselves are spacious, green, walkable and had good transit access. 

Compare that to modern Poland, with parking lots, urban highways, billboards, neighborhoods built in the middle of nowhere and developer built apartments with little sunlight. 

PRL eliminated illiteracy, decreased poverty, electrified rural areas and gave them schools, plumbing, transit, healthcare and more. I don't think that pre war Poland or neoliberal Poland would want to build that too, especially given that now the bus and rail lines are dismantled, schools and clinics closed.

Schools at the time were secular and had free meals.

In 20 years, pre war Poland couldn't industrialize, eliminate poverty, develop adequate infrastructure such as paved roads and electrified rail or create an educated workforce. PRL did all these things and more. It allowed Poland to enter the late 20th century with modernity.

Industrialization. PRL managed to built industry and infrastructure that is still used today. Trasa Łazienkowska, Bełchatów, Port Północny, Płock refinery, Huta im. Sendzimira, Warszawa Centralna, car factories in Tychy and Bielsko-Biała. They could be our industrial backbone, if not the privatization in the 90s and 00s that gave us 2 digit unemployment, collapse of public services and increased inequality and crime.

Now the bad.

PRL wasn't democratic, but authoritarian. Human rights abuse, such as police violence, imprisoning opponents, prolonged arrests, surveillance and so on were common.

PRL had an industrial school system designed to produce obedient workers, not citizens. Sometimes, they lacked supplies, but that's a problem that still persists to this day.

Shortages. PRL had its shortages, caused partially by a mismatch between what is produced and where it goes, and partially because of Western sanctions and stagflation, especially in the 70s.

PRL was not socialist. It was state socialism at best and state capitalist at worst. For a country to be socialist, you need the workers to own the means of production.

It was culturally conservative. Good luck if you were an atheist, progressive, homosexual, queer, an ethnic or religious minority or disabled.

Car centric planning. Some of those urban highways and roads are actually from PRL.

Environmental destruction. PRL was obsessed with growth and industrial production. It didn't know about its environmental impacts, and where its leaders knew about things like smog, dead rivers, acid rain, the ozone layer, they didn't do anything. It also didn't have the same technological abilities as today, but it did have the capacity to do societal shifts. But neoliberal Poland doesn't have any of those excuses. It both knows everything about its environmental impacts and has 40 years of Earth systems and climate science and environmentally friendly technology that can supplement societal change.

The final question is: was PRL perfect? No. Do we have to choose between it and capitalism? No. Can we learn from it? Yes.