I don't think that a comparison of the US system vs. China is going to produce a clear "winner", only a list of pros/cons whose weighting will be shaped by your perceptions and bias.
The explosive growth of China hides most of the warts of the system. When you have economic growth so fast that new, uninhabited cities get built, there's obviously some excess and policy issues at play.
The US is an imperial power, and the conduct of policy and statesmanship changes in that role. While the President is the front-man and sets the agenda, the work is done and policy is made by anonymous officials in the sprawling bureaucracy. And I betcha if you analyzed a Chinese and American bureaucrat, you would find that they look, act and think alike.