You are fighting a losing battle here I think but it is a reasonable question. In political studies folks often use economic success as a proxy for evaluating the quality of governance, by that analysis the US system would score highly. and African feudalism would score poorly. However such discussions are fraught with conditions, such as what are the natural resources available? What are the hindrances? China makes an interesting case because its economic growth under strict communism (Mao's model) was quite poor, whereas its economic growth under a more capitalist system (Den Xioping's model) has done much better. But its also perfectly valid to wonder if economics is a good proxy. What about life expectancy? happiness ? hunger?

Ultimately though you are going to run into debating philosophy and that makes for wonderful rhetoric but few conclusions.