a lot of people think the 40 is silly because it sits between 9 and 45 and all three have similar TB. I've seen people argue that the 45ACP is ab obsolete cartridge because the .40 is a small but noticeable step up from 9mm in energy on target and nothing more is gained in terms of energy from leaping from .40 to .45. They argue all you get by going from a .40 to 45 is less capacity and the same (more or less) energy.
Personally, I find it all to be silly horseshit. Shoot what you like, don't worry what other people like. I like all three calibers and have several guns chambered in each. If someone tied me to a pole and said I'm going to shoot you in the chest, would you like to be shot with 9, 40, or 45?...I don't think my answer would make any difference.