I have been told that my view on what makes a good defensive handgun belongs to the age of the dinosaurus but here it is anyway.

1. Reliability. (pistol not revolver)
2. Must have a safety under the thumb on the frame. (Not a heavily advertised device that pretends to be a safety catch)
3. Sufficient caliber.
4. Easy to carry. Light and compact even if capacity suffers a bit.

My wife's 45 is a compact I built from a 1911 with an alloy frame and is slightly smaller than a Star PD. I carry a somewhat modified PD. Both are as reliable as an anvil.