In the past EK has been considerably more generous with benefits than QF, so if that matters to you book the EK code and not QF on EK operated flights. You can view the current policy on qantas.com web site, but it has changed several times over the years so it may change yet again prior to your flight date. Personally I view booking codeshares for benefits as fraught with peril and never turns out for the better. Lots of reasons that the operating airline is preferred. Lounge access would be identical but charreur drive could vary.