IME it all depends how full the aircraft is.
On my last trip to the west, the SYD-PER flight was on DJ and the PER-SYD return was on QF. On DJ, I purchased a Blue Zone seat and the middle seat was empty, so the comfort/space was fantastic. And the food was great - on longer flights they usually offer a choice of two hot meals and the one I selected was restaurant quality for about $7.
The return flight was a dog.

It was one of the ex-MH 2-class 743's which are starting to look a bit shabby IMO. I asked for and was allocated an exit-row window seat at check-in - this turned out to be a bad decision. Leg room was impeded by the emergency slide on the door, there was no window (it was blocked off), and the plane was almost packed to the rafters. My row was full and not very comfortable. The worst thing was the "free" meal - the most disgusting I've ever had on QF and simply inedible. Thankfully the crew member in our section was friendly.
So while I prefer to sit in a wide-body plane to a single aisle plane on longer trips, my last experience was that DJ easily beat QF. At least you can guarantee an exit row on DJ and when you have to pay for food, the quality has to be decent.
QF parks the 743's on the jetbase side of the rotunda section of the terminal at SYD T3.
Edit: Forgot to add than I noticed something new on my DJ flight last Friday...
There is now a separate in-flight service guide in the seat-back pocket that lists not only the food/drink available, but also a more comprehensive Live2Air guide.
In this guide, it shows a new offering (at least new to me). Three channels are now dedicated to showing movies on flights longer than 2.5 hours. There is a selection of movies to choose from and cost is $9.90 per movie. Nice addition.
