.380 in the hand is worth two .45's in the safe.
Beyond that, shot placement being the same (I can shoot a .380 no better than a .45), the increased diameter, sectional density and energy of the .45 have got to increase your odds. Sure someone will argue that they've got this magic load for the .380 that has the energy of the .45 while expanding to the size of a dinner plate after penetrating ten inches but hey, you can get magic bullets for the .45 as well.
Once you get to the realm of 9mm, 40, 44, 357, 45 you getting more to an argument of velocity vs mass, capacity, reliable expansion etc. At this point you pays your money and takes your choice.