Many claim that A/S = All Season tires are a bad compromise. Therefore suggest either summer/performance tire AND/OR winter [M+S=Mud+Snow] tires. I'll encourage others to post knowledge of specific tire performance observations. Be aware of "standards" and note variations may well exist between "Brands". (I am personally biased toward Michelin) I'd suggest 3 general tire use goals: 1- maximum efficiency - factory aero wheels & covers 2- maximum grip - summer tires; performance tires; track tires - are all these 3 types different?? 3- best winter tires - snow; M+S [Mud+Snow]; rain tires - are all these 3 types different?? A lot of variables and where you drive must come into consideration - yes?