One of the main reasons I left is that I could never afford a house, or even the down-payment on a mortgage. If I had lots of money then New Zealand would probably be more appealing to me, but it's not a good place to earn it. I don't know if you'll be able to get a very competitive salary, but it might be worth it if you're really excited about the company, and you'll be working on some really interesting things.
One thing to mention is that most shops will close at 5pm, and many cafes even close at 3pm. I think once a week, the shopping malls will stay open until 10pm. The streets are completely quiet at night, and you won't see anyone walking around. After living in bigger cities for a while, I'm always really shocked when I go back for a visit. It's like a ghost town. It's an important factor for me because I work remotely, so I hated being stuck at home and having nowhere to go at 8pm.
Another very important point: You will probably have to cook almost all of your own food at home. Going out to eat at cafes and restaurant is extremely expensive, and it's probably not something that you can afford to do every day (especially not on a NZ salary.) I'm used to living in cities where it's normal to eat out at restaurants most of the time. But you can't do that in New Zealand unless you're very wealthy.
Anyway, it's great if you want to live somewhere quiet and raise a family. You can also spend lots of time at the beach, and go for walks in nature. But you can do that in lots of other countries, too. Personally, I prefer to live somewhere a bit more vibrant, where there's a lot of opportunities and things to do.