The folks at the satirically named War Is Boring website have an excellent long article arguing that China's large People's Liberation Army is vastly overrated by the militarily naive MSM. The huge numbers of Chinese troops deflect attention from the antiquated weapon systems most of those troops operate.
For example, more than half of China's air force is flying 1980s vintage jets. Most of its many tanks are from roughly the same era and are copies of Soviet models. It's soldiers are mostly so-called "leg infantry" that is unmechanized and immobile as a consequence. Even China's Navy which has some modern equipment is mostly a littoral defense force.
Understanding the role of the PLA requires grasping the insecurities plaguing Chinese leadership. In fact the PLA mainly exists to hold together modern China, including restive Muslim Xinjiang and Buddhist Tibet. While the PLA's equipment is elderly it would be effective in suppressing internal dissent against crowds armed with sticks and rocks.
A final note concerning the PLA's questionable effectiveness: PLA corruption is rampant with rank for sale and government funds diverted into generals' pockets. And the most insidious difficulty China faces is the demographic outfall from their one child policy:
China will grow old before it gets rich.If you would understand what the U.S. faces in Asia, reading this comprehensive WIB article is an excellent beginning.