I never ask for an upgrade. I feel rather awkward and stupid asking for something that I really should be entitled to. The one time I did OLCI at Hilton SYD I got upgraded to the top suite available there - go figure, that property is notoriously stingy with room upgrades IME.
These days I'm pretty grateful to get the room category I booked, Exec Lounge access , decent wi-fi and breakfast. Anything else is a bonus.