Auckland cannot reallly be considered a big city at a population of 1.4 million, I guess it's relative of what you're used to. The factors to consider living in Auckland are :

Housing - overall central suburbs are very expensive and older houses are not insulated for the climate. Insulation is an essential requirement, as Auckland gets a lot of rain for 8 months of the year. You have to travel long distances to live in affordable, more modern structures.

Traffic - the North/South development of the city causes a lot of traffic congestion. Parking in the city areas is very expensive, forcing more commuters to use public transport. There are Bus facilities in the North, and both Bus and Train facilities in the South.

Auckland is the number one destination for immigrants because of job opportunities.