old building with taller ceilings than new build apartments. larger windows etc. is this correct?
In some towns, especially in the west of the country. Not all are in good condition. Many were damaged in the war and poorly rebuilt (without the architectural detail) others are OK.
I'm not sure why you call them that - such blocks were built throughout Europe, certainly not only in Warsaw Pact countries. Some are good places to live, others not. Polish blocks being often cooperative rather than city owned do tend to have a wider socioeconomic spread of residents compared to, say, the northern parts of the UK.