#1 concern should be manufacturer...#2 should be application...#3 should be tread design...#4 should be cost in your quest. Lastly should be the date of manufacture. Actually the older the better, and this of course knowing that those inventoried at the place of purchase won't be that old anyway.
The advantages to buying a older tire far outweigh those of buying a newer. Actually buying the newest possible gives the buyer only 2 advantages: dry road traction and a slightly better ride...the fresher the more elasticity they have. But this is short lived and goes away quickly.