Is there anything nice to say about private equity funds?

Robert Reich gives this scathing criticism of private equity funds. What can be said in their defense? There must be cases where they end up increasing the net efficiency of a company. Suppose the profits were not treated as capital gains. Would they still be profitable? It is true that they work with other people’s money, but people are only going to use them if they show a good track record. As a liberal, it is too easy for me to just nod my head at what Reich says. I am trying to get a broader perspective.