Breaker,
I'm pretty sure it's not "tax free" for the chinese company, that gig doesn't exist anymore. What actually exists is you are free from double taxation and the chinese give you a tax receipt for what you pay in china. So you might end up paying 10% over an above that depending on what province you live in, as well as your CPP and EI. Still better than KAL at this time, but they might have up the ante soon as I hear their floodgates are open with the USD plunge and 5 years of frozen pay.