Let's see, then. Based on the Visa rate posted for yesterday, June 24, and today's Bank of China rates, US$100 will get you the following:
649.84 RMB (ATM/Visa)
651.97 RMB (TT/BOC)
646.67 RMB (Cash/BOC)
That is, the Visa rate is about 0.33 percent worse than the TT rate, and about 0.49 percent better than the cash rate. (Of course the posted TT rate doesn't include bank charges that usually accompany TTs.)