Since you're clearly referring to pvg (the airport) in your second statement I'm guessing you are referring to it in your first statement as well and that you're going to be there for a layover during which you'd like to make phone calls. Are these assumptions correct? If so Mobile would be my pick because it has the best call quality. For data the airport wifi is slow but not much slower than 3g. They are are easy to buy and wifi is fairly straight forward. You can log in with a phone number.