"Transparent" vs "opaque" governments strikes me as a false dichotomy. There is certainly a spectrum of transparency and I grant that the United States is more transparent than China (at least from my perspective inside the former), but keep in mind that Snowden is still facing charges if he comes home and Manning just got free after her latest round of detainment. Considering the ways national interests interact is more useful than using transparency as your measuring stick for everyone.
Transparency International ranks the US as number 23 and China as number 80 in their list of transparency/corruption. They are not in the same quartile and can't be considered similar in transparency.
Don't overgeneralize: The page you linked explicitly lays it out. Corruption Perceptions Index. Each word is important. In addition, think tanks have biases and TI is no exception. Do you think that the "experts and business people" they interview to calculate CPI have interests which may align more or less with different nations?
In any case, I opened by admitting my perception of the United States is as a more transparent actor than China. Still doesn't make a dichotomy.
