Cost of living in Auckland and Wellington is high (rent and food, mostly), but great fibre internet and huge demand for engineers. Big days rates from what I've heard (I'm in London now).

Auckland is on two harbours, absolutely beautiful geography, but you'll need a car and it can be a congested, frustrating nightmare. Lots of smart people though, universities, cultural stuff etc. GREAT food. Seriously good - loads of Asian migration will do that.

Wellington is much smaller, also beautiful, but worse climate. Lots going on though, for a city of its size (150k cbd, 400k wider area). Is the capital, so combination of liberal arts educated public servants, HQ of Xero and centre of film industry (including Weta Digital), 2 universities both with strong creative schools, HQ of national ballet company, HQ of national orchestra and lots of other stuff makes it a pretty great city intellectually. Really cosmpolitan, also great food, but the asian food isn't as good as Auckland. Great local tech scene and lots of creative people.