Quim,
The Qantas 330's are safe. But I wouldn't fly in the Jetstar 330's for quids!
Other than the coat of paint and the Int J class config on the QF op 332 versus the "borrowed" QF 332 in Jetstar W class / QF Dom J class config with leather covers, what's the difference?
As far as I can tell from casual observation at the gate, all the J* 330's are in mainline rego, with mainline engineers doing the pushbacks, and mainline engineers doing the line maintenance when the birds are parked - or has something changed?