Career wise, you will not beat QF. There is no other airline on the planet offering the work/life balance these guys get. The coin is good. Good options to live where you want, work when you want etc etc.
Down size is limited network. Domestic its the magic round about, same places over and over and over again. International its pretty much the same, it wont take long to have been everywhere they go, again again again and again. But its just a job where you get to fly and it finances a great lifestyle lifestyle for you and the family. You will not find a better package than QF.
Overseas works for some, not so good for others. I am lucky, as it works for my family and for me. The kids have grown up all around the world. They have friends from all over the world, and have established themselves outside of OZ.
The network the fleet I fly on still has places I haven't been to. It has a mix of short haul, 1hr, 2.5hr and 3hr sectors, as well as ULR (ultra long haul 16hr+), and everything in between. Once a month I take the Mrs for tapas in Barcelona, or Pasta in Milan, or fish and chips in the UK. We spend a weekend at the beach in Mauritius, or have a beer in Prague (you get the idea). All while I am at work. I buy my parmesan cheese in Rome, Rioja in Spain, Pork from Germany and the Chrissie ham from Brissie.
But the buggas work us hard. They find it difficult to communicate the truth. If you took it seriously you would go crazy. Check out the Middle east forum to see. As I said, I am lucky. My wife and kids like it over here. They have taken the opportunities that are available here and made it home.
So my recommendation would be. Go for QF. Buy the house you want, where you want. Send the kids to school you want. The rest will all work itself out.