NZ is an interesting question for us.
Our two older boys have both been to Queenstown/Cardrona - twice each. One in 09, both in 08 and one in 07. They went on school trips in July.
We often talk about going to NZ, but always end up in Aus over those school holiday weeks. The drawback for us is driving up to the snow each day - we really like our walking distance accommodations - especially with teenagers who wont hurry up and get ready for first lifts.

When we ask the boys who have been to both whether they would rather go to Cardrona or Thredbo with the family they choose Thredbo, but I suspect that has a lot to do with the drive up each day. Number 2 son is talking about doing the Snow Trainers course in NZ rather than Niseko now (as it will give him an extra 6 months to save for it)....so he is certainly not against NZ.
Would it make a difference if we were on the East Coast? ... maybe ... but if the Aussie snow was easily accessed by just a drive I think the difference would be that we would consider NZ less.
I don't know Jynxx.
It is easy to head off for some Northern Hemi snow as we don't have any on our own soil at that time of year - the battle I have is that I always want to go back to Hokkaido and Papa wants to see the world. But when it is the Southern Hemisphere and I have had some awesome days in 'my back yard' I don't really see the attraction of playing in my neighbors yard - except for the novelty factor.
But ask me again after I have been, and you might get a different answer. I am learning and changing my opinion all the time.