You also need to ask the following questions

1) Any tax equalisation benefits. If no, you have to pay higher income taxes in China
2) Any home leave. How many times a year? If no, you have to pay your own air tickets if you want to come back to SIngapore for X'mas, Chinese New Year, etc.
3) What kind of lodging provided? Staying in the factory hostel?

If both 1 & 2 is no and 3 is yes, then it is very much a local package and you cannot expect much.