They shot a few people with .32 FMJ during the war as well.
Must mean it's a good choice.
Personally I'd carry a 1911 .45 or a Glock 22 in .40 if I were a cop. The .40 is thrown in simply because it has a much better capacity than the 1911 and I think its a fairly decent compromise between 9mm and .45.
The best .40 loads are almost identical in performance to the best 9mm loads.