I had a .40 once. Discovered that I couldn't shoot it near as well as either the 9mm or the .45. Tried several factory loads and uncounted handloads, but the accuracy just wasn't there. Might have just been my gun, but I've never bothered to buy another to find out.
I'll stick with my .45s. I shoot it well and am completely satisfied with it.
I notice that some of you .40 lovers seem to be a might touchy about others putting it down. Kinda like Glock owners.