Wellington isn't as windy as our reputation states. There is generally a breeze and one or two big wind events every year. But like much of North America and Europe getting snow, and much of Asia getting the monsoon, Wellington is built to handle it. Buildings are designed to provide wind breaks and even get tested in wind tunnels to make sure that they don't act as a funnel. Generally the weather is pleasant, in Summer it doesn't get above 25 too often, and in winter it's seldom below 10 in the days and 6 at night. We get a frost only a couple of times a year.
Wellington has a large inner city mountain bike park, one of the largest inland ecological islands within the city boundaries, and a much more convenient access to nature and the outdoors than probably any other city in the world.
Auckland is much larger and warmer. Number of beaches around so the culture is more around surfing. Also quite a few nice hiking areas ~1hr drive away. I only been in Melbourne and SF for a few days, but Auckland definitely beats them in quality of life.
Xero is always seem to be hiring something. There is also a strong albeit small group of functional programmers (find via meetup.com).