If anyone chooses it, factory ammo will not be as efficient as rolling your own. The barrel, at 2.5in is too short for anything but the fastest powder and lightest bullets.
I recommend the .40 with the 150gr Nosler HP backed by 8 grains of Hodgdon Longshot.
Very hot load, not for plinking. It will wear out your pistol...but should still give you about 1050-1100fps for that 150gr .40 out of that 2.5in barrel.
Adequate. If you can hang on for follow-up shots.