Probably, for anyone going out to China for the first time, the best bet would be using some form of Credit and ATM card(s) Obviously following all the safeguards that has been mentioned, like informing your bank when and where you will be, so as not to have the card blocked!!
But i would also suggest that you take an emergency contingency amount with you in your own currency cash. Cash that you have no intention of using/spending except in an emergency!!
Never change up more than you would need for 1 or 2 days in your own country, you will ALWAYS get a better rate for your cash in the country you are visiting, the exceptions to this rule are very few and far between, and China is not one of them!!
Somewhere in these threads, i have previously posted a do's and dont's list on money changing in China, if you can find it, ....it will explain a bit more than i have here!!
Another observation on this thread. It is illegal to change foreign currency for RMB in China or visa versa, except through official designated banks, so never change your cash with touts outside the banks. You could get yourself in a whole heap of trouble, you could even find yourself dealing with the fraud police/officers, and a hefty fine at the end of the day.
You should only deal with people you have been introduced to, are known to you, or with friends!!
David.....