See China for yourself my friend, judge with your own eyes and experience if you can. Maybe its good maybe its bad, maybe its somewhere in between.
I had been to both the mega cities in China and the US, they are different. Many parts of China's large cities are still developing and the developed parts are active, vibrant and clean. Construction sites can be messy. Also the so called "ghost towns" are not common, the NE's 3rd and 4th tier cities has some of these districts due to the mining/steel boom and bust, other regions are fairly well off.
The average pay might not be as high as NYC but you will find saving money easier with a comparable lifestyle (it could also depend on your lifestyle). A smaller US city has affordable living but high paying jobs are more scarce since some high end industries tend to be concentrated in large cities. Not to bash NYC (its great in its own way) but the subways are not as clean compared to subways in China's mega-cities, some station can be very dirty. In NYC you will be bombarded by lights and there is a lot of activity, privately owned high end places are well kept. It is a vibrant city but in certain blocks, getting mugged is a common occurrence (in Manhattan) and overall not as safe as China's cities. Sometimes there are shady looking people/groups wondering around (and some people don't like to see their presence as a preference). Staying vigilant is key.
In NYC people like to stay in their bubbles because it is secure and comfortable, in Shanghai, Beijing or Shenzhen it isn't risky to venture out of it.
Paris has beautiful architecture, cultural relics and the local French people are generally fashionable. It is worth the trip but living there is questionable (for various reasons). A lot of gypsies (they mainly hang around the hot spots) trying to steal your things in broad daylight and some Africans trying to sell you Eiffel towers (tend to be much friendlier than Gypsies). The streets are quite narrow, not exactly modern city planning but that would depend on preferences.
France overall is a decent place but it is not exactly the France of the 19th century that most Chinese have in their minds.