You can read here seven things that Prof. Andrei Shleifer, one of the world's leading economists, has learned about the transition from communism. Shleifer and a team of Harvard economists were instrumental in providing policy advice to the Russian authorities in the 1990s. It is surprising that despite the failure of the 'big bang' approach to the privatisation of state-owned enterprises in Russia that Shleifer still advocates that privatisation in transition economies should not be over-planned or delayed. However, Shleifer's credibility on this issue has been affected by some conflicts of interest which arose for him whilst advising the Russian authorities. These conflicts of interest ending up costing Harvard University millions of dollars in order to settle a lawsuit against it. You can read more about this here and here.
It has only been 20 years since the beginning of the transition process in former communist economies. It is still far too early to say whether this transition has been a success or otherwise.