Was also on the flight on 14/04 (OEG as well which was a welcome change!) - seemed to be a few spare seats in the business cabin (but couldn’t bag an upgrade from the lounge on the way out as I was only in economy!) Premium Economy was just the seats with Economy service, completely unsure how they allocated it (kind of interesting because I had paid for up the front seats with JQ).
As has been mentioned was full QF service with baggage included, and I was in 43C, being the first row of economy and was a very welcome change compared to JQ.
Excuse the shocking photo but full QF service as you can see and included free alcohol throughout the flight!