Depends,
Allies have more stable support weapons (less recoil). Sniper Rifle is more crisp, and like the rocket class more than axis.
Axis have the k98 which is insta kill heaven if you can aim, the Axis support does more damage if you can handle recoil and the machine gun sprays more than the allies. (Allies seems more accurate to compensate though).
Prefer Allied knife over Axis shovel as well.