This question is probably best answered in the Dununda forum.
It's been a few years since I've worked in Australia but from what I can gather, it's a hiring boom Downunder.
Historically, Qantas rarely hired from their own regional. So if you think that going to Qantaslink will give you an inside edge into mainline, forget it.
A regional captain generally earns less than a jet FO so why not go for Virgin or QF? What have you got to lose?
The tests for QFlink are pretty much the same for QF mainline so you may as well have a go.