Hamilton himself has said he prefers a neutral car. It's just he generally deals well with oversteer because of his quick reactions and so now has a reputation for preferring that.
Staying with Monza, will he or anyone else get much opportunity to use oversteer? Perhaps through the first chicane but would oversteer not slide the rear end of the car in the Parabolica?
I dont think oversteer is an option on the steering wheel like kers. I am not sure drivers 'get the opportunity to use oversteer' in that sense.
Oversteer is what you get when a car stops going around a corner like a train, and starts complaining and threatening to do its own thing. If the driver can let the car do what it wants a little bit yet keep control then he is ok with a car that tends towards oversteer. This will ofcourse mean that its setup to handle the mix of sectors on the lap as fast as possible and on this corner it wants to lose rear grip, but ofcourse the driver is ok with that.
Neutral handling and balance is generally a good starting point for most corners, however the special drivers can handle corners where the car threatens to spin off the road allowing the car to be setup faster round the other calmer corners
Heres a good start
http://en.wikipedia.org/wiki/Understeer_and_oversteer