As was mentioned, the only really need for 40 S&W is if you shoot IPSC standard division. It is a bonus there as it is milder to shoot than a 45, and it can easily maintain 10 rd capacity. As far as straight target shooting, a 9mm is definitely easier and cheaper to shoot and just as accurate if not more so. For defence, forget it, we cannot use handguns to defend ourselves here in Canada. I would personally prefer a 40 over a 45, but other than that, it is 9mm all the way for ease of shooting and affordability.