I can only speak for the airline I work for, but have heard nothing different from other pilots in China, as compared to the ME. You are a citizen of your home country, working on a work Visa in China. Your passport is your own. Break a law (including being involved in an aviation mishap) and all bets are off. That exists in all countries, however. Other than that, you are a foreigner, and free to leave at any time. It is far more difficult to stay here for most foreign workers, than to leave.
Overall: No BS in that regard, specifically like Qatar Airways where they hold your passport while "in country".
Goods in China?
China is welcoming to visitors, including foreigners working there. That is their culture.
Money is very good.
Economy is stable, for now. LOL
If you work for a good company, or just get lucky, you will be treated like a rock star.
Bads in China?
No english, bad air, gotta be careful what you eat and drink, gotta be careful about medical care. Same Same many places.
They fine you for QAR events. It is their law, and also applies to their local pilots, and if you get one, they also charge the last check airman that signed you off.
If you work for a bad airline, they might tell you that you require additional training, by them, at your cost. I have heard this happens a lot, but not at the airline I work for.
This is all I know, after 8 months.