I know this thread is old, but the debate is eternal :-) I wanted to share an impression. After spending 3 nights in a Wellington suburb (Karori), we came to the surprising realization that we might be better suited to Auckland after all.
The main factor? The roads. They are SO NARROW once you get outside the CBD. Once people park on the sides, there's effectively one lane left. I won't say they're all like that, but too many for my taste. I frequently found myself driving squarely over the middle line on very twisty streets with blind corners. I'm told you get used to it (and to parking on the grass when the street is even narrower), but even as somebody who grew up driving around windy hills, it was stressful. Also, traffic is no picnic, with not much in the way of backroads to avoid the fray. We didn't have to drive at peak times, so it would be even worse with a regular job.
The other thing was that the named suburbs such as Kelburn would often have only one or two blocks worth of shops, which means you would need to drive into the city for many necessities, or to a bigger suburb. I imagine we would order delivery more than we would avail ourselves of the downtown restaurants.
Karori itself actually had a decent village, with all the basic necessities (grocery, post, etc) and even a nice library branch, and benefitted from straight, normal roads in the central part. It was just the inconvenience of having to drive through the more labyrinthine areas in order to access the CBD.
Auckland may be a massive sprawl, but because of that, the suburbs did have a decent variety of offerings in each one, so you're not stuck with the same five dining/shopping options when sticking close to home...and you don't have to drive over the center line of the street to avoid parked cars on the way to work :-P
Weatherwise, we didn't love Auckland's humidity and random downpours, so you can pick and choose between that and Welly's windchill, lol...