I shoot 9mm and 45acp. 9mm because its cheap and has a great selection . For trigger time it's hard to beat the 9mm price.
I don't see anything wrong with the .40 .
I have all calibers and ammo for everything but shoot 9mm the most as it's much cheaper.
If I could get .40, .45 and .357 Sig for the same cost I would happily blast away with any of those.
I'm on the ragged edge of needing to start reloading again as it is with 9mm so that may change.