.40 S&W.......
40 Short & Weak
9mm with a good +p hollow point is better than .40 s&w. All you gain with the .40 is a little more energy (which means practically nothing anyways) and recoil.
9mm is cheaper, easier to find, easier to shoot, holds more rounds in the magazine, is more universal all over the world and is more accurate than .40 S&W.
I'm not saying .40 S&W is a bad round but the only real advantage it offers over 9mm is that it leaves a bigger entrance wound. The wound channels the best .40 s&w defense ammo makes are not much bigger than the best 9mm.
To me, all you gain with .40 S&W is price, recoil and lowered capacity.
I just thought I stir up some discussion with this post!