[dutchman1]

Tires that work on everything (all seasons) are always a compromise, by nature.

Summer tires want to be more sticky, tolerate more heat, and have stiffer sidewalls to deal with the lateral loading caused by the increased traction.

Winter tires want soft sidewalls (conforms to the road/snow/whatever better), a compound that performs better in the cold, and lots of tread to grip on softer surfaces like snow.

The rubber used in winter tires will overheat in the summer, and the rubber used in summer tires will harden and not provide much grip in the winter.

All season tires are designed to be able to handle everything, but by definition don't excel at anything.

Optimally you'll get a good summer tire, and a good winter tire. Run the summer tires all year, and then when the mornings become frosty, switch to the winters till it warms up again.

That being said, you'll still notice an improvement from what you have now by switching to a sportier all season tire, like the Michelin A/S or the Continental DWS.