Join Date: Feb 2013
Location: Irvine CA & PEK
Programs: Hyatt Globalist, Marriott Titanium, Hilton Diamond, IHG Spire Ambassador, Qantas Platinum, United S
Posts: 664
I have the feeling that for CNY transactions, we don't have the worse rates of Visa. This could be because that CNY is not a market currency.
To compare market currencies, I looked at the different rates for 5-22 on their official rate sites, and found for CNY, Visa is actually a little (0.1%) bit better; but for AUD, MC is like 1% better than Visa (you can see this by simply looking at the rates shown on their websites). For EUR, JPY, and GPB, they are about the same.
My Barclay MC uses transaction dates' data, my Citi MC cards use transaction dates as posting dates, and my Chase Visa uses posting dates' data. This is the major difference I've found so far.