The fact that there were a sufficient number of emigrants that they were prevented from leaving by travel prohibitions, walls, barbed wire, minefields and snipers should tell you about living conditions by itself.

The majority of people in every place where media is tightly controlled will believe what parents, teachers, papers and TV tell them. North Koreans have a positive view of Kim Jong Il, mainland Chinese have a positive view of Mao. That doesn't mean that either of them weren't objectively horrible in terms of competent leadership or morality.