All-season tyres will generally offer improved grip in wet weather and low temperature conditions, as well as on ice and snow. However, this means they will also generally offer reduced grip in dry conditions compared to a summer tyre such as the Pirelli P Zero, and their tread pattern usually means they are noisier than summer tyres also.

Ultimately it is a matter of compromise between the two, unless you choose to have two sets of wheels and tyres to suit the season.