First of all. There is one nexus between all system of government, that thing is called "Justice" to some it is called "Equity" any system of government that lacks Justice or Equity is nothing but a conjecture of  hypocrisy and cruelties. There is no system of government that is perfect or without defect, be it socialism, capitalism, feudalism, autocracy, Aristocracy, theocracy, to mentioned but view. Each of all these system of government has been tested by one country or the others and non has guaranteed peace and harmony. However, the perspective of the people being governed and the ideology of the governing powers will determine which system of government is better. Also, the cultural background of the people whether such country can be called a nation or a state. The numbers of ethnic groups be it minority or majority. To cut it short, the best system of government is the one operated with fairness, equity and justice. Thank you.