The rapid and successful conversion to market economy was the main reason we are where we are. Human cost was extremely high, crime went up quickly and lots of money was lost. I'd argue this was corrected by joining EU and by adjusting the plan to polish reality.
What made it a success was also the social capital in Poland, a lot of people worked extremely hard to pull it off, but still high unemployment was alleviated only by joining EU and people leaving to find employment elsewhere
Not to forget tens of billions in EU subsidies. Not trying to diminish the polish efforts, but not every country gets this opportunity of massive, predictable transfers without much conditionality.
I wonder how far Poland would be without the years of PiS corruption.