I spend most of my driveing life on tiny little country roads my car can either understeer or overseer depending on the way it is driven. In the lupo i have to break before a corner and power through it if i break into a corner i will get massive undersear the end up in a hedge its very very scary and once it starts to happen there is hardly anything that will correct it apart from a tree or curb. Overseer is much more predictable if i slow or brake before a corner i can then just power into it, if i start to feel the overstear i know letting off the power will correct it. You can also feather the amount of steer you put into the wheel. So driving into the corner you will almost twitch the steering wheel putting in a bit of steer then backing of then a bit more than backing off. this is ideal on a front wheel drive car you get use to the balance of the car. Its like how you drive a car up on 2 wheels you feel the balance and add the steer in to correct the car from falling back down onto to wheels or in this case spinning out.
On a front engine rear wheel drive car understeer is not as scary as you have the ability to blip the power to get the back end to swing out to correct the lack of steer.
IMO under or over is not better it just depends on the car and the ability of the car and driver to correct it and the driving conditions.
Personally like oversteer for the tight bend british roads i drive on. On long gradual turns oversteer is not as good as g-force is not with you to give the same feed back to calculate how much steer to put in so you tend to overcompensate and it gets very tiring.