My Glock 19 Gen 4

This is where I get to talk about my first gun: a Glock 19 Generation 4:

Research

First, I did a lot of research. Here are the pros of the 9mm bullet:

Lower recoil than most rounds makes it take less time between shots to reacquire the sight picture, hence follow-up shots should be fast.
The bullet does a good job with what it was intended to do, which is stop and, if necessary, kill. The internet is full of stories backing this up.
The round is cheap enough that practice (which is very important) at the range isn't overly expensive, which is good because I'm not rich. I can buy bullets for this thing for practice at around $0.33 per shot, unlike my wife's Walther PK380.
Because the bullet is smaller, it's easier to stuff more of them into a magazine (which is why my gun has 15 round capacity).

Second, the pros of the Glock handgun versus others I've researched:

The Glock is either "on" or "off". It's very simple and straightforward.
It is safe. It has a three function internal safety dubbed "Safe Action".
The size (between full size and ultra-compact) makes it easy enough to conceal but (with barrel length and bullet capacity) not weak or difficult to control.
The safety and holster combination make it "always on" when a round is in the chamber, but safe to carry. As such, using it to defend myself will take less time. I don't have to rack the gun and/or shut off a safety, I can just pull and aim.
Much faster and easier to disassemble and clean than my wife's Walther PK380.
Came with cleaning supplies and 3 magazines, rather than no supplies and only one magazine like my wife's Walther PK380.
It feels great in my hand, and the dual recoil spring on Generation 4 Glock handguns makes recoil easier to control.
Their legendary durability.

Here's another picture of it next to my wife's Walther PK380:

Here are some sound clips for your amusement: