I don't see how the first can be the case. The yuan is pegged to the dollar. This means that a yuan buys more gasoline today at 6.5 yuan to the dollar than it did at 8.25 yuan to the dollar just a few years ago.
Why some Chinese investors invest in the US probably has to do with getting a bolthole in case of problems back home. The US is one of the few countries that does not automatically extradite anyone on the Chinese government's wanted list, does not aggressively go after visa overstayers and has a large enough Chinese community that homesickness is somewhat alleviated for involuntary exiles. It's also a place where the natives actually attempt to help foreigners who face the danger of being killed back home, which is not a universal phenomenon on the planet.
Real estate prices are skyrocketing in response to rapidly rising Chinese wages, and businesses are expanding pell mell to deal with the rising consumption that has resulted from these wage increases, which have to do with productivity increases that come from using modern equipment to do things rather than the labor-intensive methods of old. There is no shortage of investment opportunities in China.
Maybe you'll have more luck in expressing this to our fellow FReeper expat-panama, who persists in claiming that it's not. I'm just a southern textile yahoo and a nativist to boot, what would I know.