Actually, pay scales in western-owned factories are pretty good but the work is boring. My cousin said the multi-nationals generally have modern factories with good lighting, clean lavatories and large mess halls. He worked for an H-P supplier and was paid 10 times his previous Chinese salary of $120/month.
He and some of his friends have quit the larger operations to do consulting work (less pay and less stress). Many of the manufacturing operations are starting to suffer because employees are leaving. The cost of training new unskilled workers and the loss of trained personnel are forcing companies to look at other countries for manufacturing, such as Sri Lanka. Also, workers have demanded more pay and received it, an added incentive for companies to look elsewhere for cheap labor.
Finally, despite China’s size, the labor pool is actually shrinking, due in part to the one child policy and later marriages (my cousin and his wife did not marry until he was 50 and she 40). The benefit of a shrinking labor pool means more for those with skills that are in demand; My cousin and his wife now have a combined salary of US$60,000 but it would probably be four times that much here in the US.
I can confirm based on an acquaintance's experience that Chinese pay at domestic firms is closer to $120 a month than $1200 per month. Of course, the work at domestic firms is less tightly audited, allowing for a kind of bonus pay via pilferage and/or kickbacks. Unfortunately, this stuff goes way, way beyond taking office stationery home.