Virgin, no contest.
I've simultaneously held Platinum status with both, so I'm reasonably qualified to comment. After more than a decade as a hard-core Qantas loyalist, today I take maybe 10% of my flights on Qantas/ DeathStar.
There is NO culture of Customer Service at Qantas. Individual staff members might have it, but the company does not. Virgin does - this difference is at the core of the disparity between the two airlines.
Qantas has lost the plot, with no prospect of recovering it anytime soon.