There are other things to consider besides either 9mm or .40. Are we thinking about having a pistol built or picking one up and see how it runs? Single stack or double stack?
Let's just say for under a $1000. You can get a STI Trojan in both 9mm or .40, and both Kimber and SA market single stacks in .40. SA also sells a .38 Super and 9mm. You can find Colts in 9mm and .38 Super if you look. PA makes their LDA in .40. If you want to spend a little more money, you can get a STI double stack in 9mm, .38 Super, or .40.
With respect to how they shoot, I like a .40 better than a 9mm. Seems to shoot a little faster. The only 9mm in a 1911 I shot was a Colt. It just seemed slow. If Tom gets into this thread, I am sure he can add more to this than I. I think he is shooting a STI Trojan in 9mm.
"And by the way, Mr. Speaker, The Second Amendment is not for killing ducks and leaving Huey and Dewey and Louie without an aunt and uncle. It is for hunting politicians like (in) Grozney and in 1776, when they take your independence away".
Robert K. Dornen, U.S. Congressman. 1995