Let me set things straight...I like and shoot all 3 calibers...With todays bullet technology...The stopping power and expansion rates are real close between all 3...If I had to put them in some kind of order,my preference would be...The 9mm 1st followed by the 45 then the 40...It seems I'm most accurate with the 9mm,probably because of the soft recoil,followed by the 45...Cost is another reason the 9mm is at the top for me...Sometimes you hear stories about the 9mm not doing the job...not enough power etc...But then again...It's all about shot placement...In regards to the 45...If you cant hit where you're aiming,it's still gonna cause alot of damage...It seems the 45 theory about,"Bigger bullet...Bigger hole" holds rather true...I guess it all boils down to what you feel most comfortable with...If we do our part...All 3 calibers should serve us well