As you say rexw, it's all in the mathematics.

Number of countries China shares a land-border with: 16. (This doesn't include Japan or Taiwan).
Number of these who are allies: 2 (Burma and North Korea).
Likelihood these countries will ever trust China, particularly while China has a secretive approach to policy forumulation: Slim to zero.

Number of countries America shares a land border with: 2
Number of these who are allies: 2

US GDP Per Capita per annum: (2010) $43,000 USD. (Ranked no 9)
Chinese GDP Per capita per annum: (2010) $2,000 USD (Ranked 95)

(It's also worth noting that in most advanced economies, growth slowed dramatically when GDP hit the $7,000 per annum mark. This was true of both South Korea and Japan. The difference is, that if Chinese growth slows dramatically, this causes extreme political instability).

Military expenditure:
US: (2010) $670 Billion USD.
China: (2010) $100 Billion USD approx.

http://the-diplomat.com/whats-next-china/china-in-numbers/

The world's 100 most recognized brand names:
Number of them that have majority Chinese ownership and were developed in China: 0.

http://www.businessweek.com/magazine/toc/06_32/B399606globalbrands.htm

(I haven't gone through and identified the American ones, but there are many there).

Financially, China is doing well, but this is far from assured into the future, the challenges China faces are more immense than for any other nation including America.

On every other measure, they are well behind.

America has already suffered their recession and are now slowly recovering. China's will be more brutal when it comes, and the results are likely to be uglier.