I may be in a unique position because I've lived in both places. I'm from Adelaide originally and now live in Canada, so you may want to factor that in.
New Zealand is nice, wages are low, but most stuff is inexpensive (rent, etc) so you'll get by fine. The accents are really grating to an Australian and I found that while I was there I could not stand listening to the radio. The people in general are nicer and more helpful than in Australia, I would say it's like Australia used to be 20 years ago. I lived in Christchurch. They like their Rugby (Union) and for some reason Coronation Street.
That guy bagging out Sydney is from Melbourne, and everyone knows there's a rivalry between Sydney and Melbourne. I've lived in both places, and I prefer Sydney, but both are very nice. You may say I'm biased coming from Adelaide, but then my missus from Canada also likes Sydney more.
Immigration for New Zealand was much easier than Australia, I don't know if that's still true. There was a time a while back where immigrants would do their stint in New Zealand, then use the Trans-Tasman Agreement to get into Australia because of the easier immigration. As someone noted earlier, you can't do that as easily anymore.
Frankly I got out of Australia for a number of reasons, one of which was the housing prices, another, the fact that almost all IT work is contract based, meaning I had no chance whatsoever of settling down. New Zealand is still more reasonable for housing, and if you have a bit of money with you when you go there, you'll probably start quite well off.
