I am on the QF29 MEL-HKG tonight (departs in about an hour). I chose the QF flight for a few reasons:
Departure time is 10:50pm vs something after 1am
Waitlist for F upgrade with QF using QF FF points (which cleared )
QF FLounge is excellent, and I believe it closes after the QF29 flight boards (may be wrong here assumption??)
QF flight is guaranteed to be Skybeds, while the CX aircraft is occasionally subbed with a regional config.

However, on my return LHR-SYD I have selected to use CX to try out their new business class seats.