Bit of an old thread, but thought i'd put my two cents in!
My 2001 1.2 16v sporting (which is about to retire to a new home and make way for a Grande) has only ever had the steering motor go once - and that was purely my fault for having the 'city' button on 24/7 (oh, the excitement of 'city' button after driving a seicento for however many years! Let's just say I went a little OTT). After replacing that motor, and obviously getting myself over the excitement of the 'city' button, I have never had another problem with it in the last 4 years.
Apart from tight maneuvers, I don't see how anyone can drive about with City on, feels like driving on ice! If I remember correctly it turns off at 19mph or something