Having flown QF for the first time since 'Premium boarding' has been introduced, I have to say, i'm underwhelmed.
Experience in MEL:
Non existant. Yes, the signs are there as is the barrier. There were two staff scanning boarding passes, and not one was policing the premium queue. Was a very full 767 flight and at least three people in front of me had no FF number at all on their boarding passes, and row numbers above 20. The gate agents did nothing but scan and welcome them on board.
Experience in SYD:
At gate 9 this morning, it was actually working reasonably. The queue for regular was snaking way back and there were only a few in the premium queue. Of course, it was a 738 so it was pointless as by the time they had announced boarding down at the J lounge, the regular boarding had commenced, and the a/c was half full by the time I arrived (and yes, I'm aware this is a regular argument of those who say 'meh priority boarding what's the point when...'

). Still, it did work.
Seems to be self-policed. If people don't see the signs (not that you can really miss them) the agents don't seem to tell them they're not eligible to be using that queue, whereas Virgin quite politely tell people to use the regular queue if they aren't.
So far, i'm not really regretting switching most my travel to DJ. I'm treated far better there by all staff than with QF (where mediocrity seems to be the order of the day).