There is no objective way to say which system of government is best. Different systems may work better in different circumstances.
For example, I would argue that a council-manager system of government is good for small cities. This system ensures that such towns (which do not have big enough governments to warrant full-time mayors and council members, will have a professional running their city operations. The council provides democratic control and the city manager provides competence.
By contrast, a strong mayor system is probably best for a big city. In such big cities, government is much more important to daily life. It would be dangerous, politically, to have a chief executive who was not elected by the people. Thus, a more elected system is better in such cases.