I carry a P3AT.
Took me awhile to figure out how to hold the thing properly to shoot well.
I had some cycling issues at first. I took and field stripped it, smoothed some rough edges, reassembled, and started jamming again.
I watched a friend shoot 2 clips through it no prob. I realized then it was my hold letting it squirt up under recoil. Sort of "limp wrist" effect I guess.
No probs after that.
It goes whereever I go, which is what defense is all about.
About the same size as my FIE .25acp, but thinner, and lighter, with much much more ooomph.
If I had to do it over, Id probably get the Ruger LCP. Only because I just show a little brand loyalty to Ruger, nothing against the Keltec.
The .380 is a fine defensive round.
A couple .356 caliber holes are plenty big enough to let a bad guys "oil" out, at defensive ranges.
(Doubt there'd be any real world difference between sub-1000fps .38cal rounds at defensive ranges. Ie:380,9mak,38spl, etc., with roundball)
The main thing to be concerned with, like you referred too, is having the gun ON you first of all. Then knowing how to use it well.
Caliber would be less important to me, than the first two.