Flatter trajectory, wider range of bullet weights, ever-so-slightly better terminal ballistics (if you believe the FBI study), and since it was designed to fit into a modified 9mm platform its firearms are traditionally smaller and lighter with a higher capacity.

Not that the 45 doesn't have its own advantages-- operates at half the pressure of 9mm/40/etc., displacement (.45") and bullet weight (hard to argue with 230gr).

Pick the one that shoots most accurately in YOUR hands.

__________________
NRA Certified Instructor