A bit odd no one has mentioned the caliber yet! The M1 Garand is chambered for the .30-06 cartridge, a much more powerful cartridge than the newer .308 Winchester / 7.62x51 mm NATO the M14 (which followed the Garand in military service) was chambered for.

The biggest problem with the M1 was the magazine construction. The magazine holds 8 rounds, the rounds are fixed onto a metal clip and inserted down into the magazine well. This construction makes it almost impossible to reload the magazine when there's still some rounds left. Also, when the clip is empty, it ejects with a distinctive "clunk", telling the opponent that it's time to attack...

The Garand is still used, mainly as a parade weapon --because of its balance, it's well suited for juggling / rifle drill!