I'll echo the sentiments re Keltec and Hi-Power. I have 4 different Keltecs.
My HP is a Charles Daly, much cheaper, nice gun, still a few NIB examples to be found.
But I don't like plastic guns for home defense. Plastic frames are for carry guns.
And I don't like a single-action for defense unless he is very familiar with them.
The P-series ruger is the Ford truck of handguns. Super reliable, but too chunky for my. I sold mine last year after keeping it since 1993 - my first centerfire handgun.
So for my home-defense handgun, I like:
Da/SA trigger
Safety/decocker
all-metal
hi-cap.
rail
The best deal right now in a 9mm that meets all these is a Stoeger Cougar for $400
It's a Beretta design with a unique barrel-cycling system - rotates instead of tilts.
Some consider it small enough for concealed carry. It's approximately "Commander size'.
Too big for me though.
Very nice gun. Be sure you get the railed version, they come both ways.