Recoil
My wife shot the Sig 232 (17oz), CZ 83, Beretta 84 380's -a11 barrels less than 4", she thought they all were snappy, and flippy, and sharp!
She thought the XDM 9mm, 32 oz, 4.5" barrel, balanced frame. heavy slide seemed to recoil slower and softer.
But I agree with catcorner...