Well, how can I say... Milan is a little bit more like London and NY than all the other Italian cities. So expect a busy environment, nightlife, restaurants, shows and so on. On the other hand the quality of the air is bad, prices are high and the weather is uninspiring: vey hot in summer, very cold in winter.
Pros you are close to everything (two hours drive for the alps and two for the sea, from St Moritz to Portofino) and with the new hi-speed train you can even have an easy lunch in Rome and back for dinner.
Best place to live is the center (inside the inner circle of the roads you may see on a map) but home prices there is very high.