I have had some success but definitely not every time.

Last month I was at the Marriott Guangzhou Tianhe for 4 nights, no such luck. Fortunately the standard room there is large and very nice so I did not mind. I have stayed there about 5-6 times and I think I got upgraded once.

Then I was 3 nights at the Renaissance Harbour View Hong Kong and DID get an upgrade. Which is very nice because the standard rooms there are pretty small. I have had success there a few times in the past as well.

Next month I am staying at the JW Marriott Hong Kong, we will see if I get the upgrade.