There are alot of good thoughts being brought up here. I think one MAJOR determining factor should be: what are your intended uses for the weapon? EDC accompanied by an occasional trip to the range? EDC as a police officer or security guard....again, with an occasional trip to the range or annual qualification course? A bedside weapon in case something goes "bump" in the night? After determining your primary need/use, I think picking the weapon should include such factors as caliber, frame size(sub-compact, compact or full size), and features. We should also take into consideration the area that we live in and the climate in the area. How you dress on a daily basis also factors in as well.
I basically carry and shoot a firearm on a daily basis to make my living. I shoot between 3,000 and 5,000 rounds per week on average. I tend to subscribe to the K.I.S.S. method......Keep It Simple, Stupid! For my purposes, a Glock is as simple as it gets. No decocker levers, no safety buttons, no grip safety. It has been proven that under stress, we lose a portion of our dexterity and fine motor skills. I do NOT wanna be subconsciously worried about all these buttons and gadgets when I am in a gun fight!! The Glock is the ONLY handgun that I would unconditionally bet my life on......right out of the box. The only part on a Glock that I have ever seen break is the slide stop lever spring. The fact of the matter is that you do not have to have a slide stop to keep the gun in the fight.
The only change that I make to a Glock is the SIGHTS. I use nothing but XS Big Dot Tritium sights, period. XS Sights are made for FAST Acquisition and EASY visibility. Frankly, they are the best sights available for killing people. The front sight looks like a golf ball and this makes for super fast shots. I have XS sights on my G19, on my AK and on my 870 12ga as well. I used all three while working in Iraq, Pakistan and Syria and I can tell you from experience that THEY WORK WELL. In humid environments, some skateboard tape(or ladder tape) applied to the grip panels can help with the firing grip if you have sweaty hands.