I bought the .40 and my buddy bought the 9mm. I've shot both side by side and am now wishing I had gotten the 9mm since ammo prices went up. The 9 feels a bit nicer too. The .40 has a little extra snap the 9mm doesn't. Also, the 9mm holds 16 rnds in the mag as opposed to 12 for the .40 I like to shoot, not just keep a gun around for show. For protection I use my 1911 .45