First of all, those $300,000/year positions are few and far between. You can make good money in China on some of the contracts, but others are less generous. There are big differences in the QOL between the carriers. There are some good ones and some really bad ones.
Every person deals with change differently. Some people absolutely hate China; some people love China; some people are in the middle and tolerate it. Again, it might depend on the city you are in; the airline you work for; and even whether or not you like Chinese food. It might depend on whether you can learn to speak Mandarin; whether you are married or single; and what your hobbies are.
The mainland Chinese are lying A-holes, no question about it. But again, some companies are better than others and have actually improved their contracts over time while others have failed to live up to their promises in the original contract.
The punishment culture of Asia is one that is foreign to us. Any mistake is met with punishment as the first reaction. Thus they have a fine system for QAR violations. Some of the airlines enforce those on the foreign pilots and some do not. Read Sun Tzu, Art of War. What was his punishment for a soldier not doing the right move in a military drill? If you guessed death, then you guessed correctly. Great motivation tool to make sure you know how to do left face, huh?
The other item that has not been addressed here so far is the Chinese medical. It is a total crapshoot to pass the medical there. The doctors are incompetent at best, but they have their little guidelines that they blindly follow. If you fail, guess what, you're going home or being asked to do a dangerous test to make sure are healthy. It's total joke and again a lottery as to whether you will encounter a problem or not.
I know a couple of guys who have been there over five years. I also know quite a few who lasted only a year or two. Odds are it will not work out for the majority of pilots who go there. For the lucky few those $25,000/month tax free jobs can be pretty sweet.
The only way you aren't playing career lottery is if you are furloughed or on a leave of absence and can afford a little adventure while you have a fallback plan if it does not work out.
Typhoonpilot