What carry gun you are comfortable with is going to be your individual decision - just the same as the thousands of posters recorded in threads on the subject. If it's a gun, it's preferred by someone as their daily carry.
Beyond that, the more snag free and the fewest sharp contours comes up a lot, as close contact and wear under clothing tends to cause conflicts with typical woven clothing. Next, the average carrier begins to notice the size and weight, and begins to consider that a 19 shot double stack full size duty gun with two magazines might not be the most optimal carry piece for confronting a shooter in Walmart. That recent event goes back to the likely use of just a few shots at close range.
What carry does bring on to the scene is having enough training. The consensus is you can't get enough. Professionals get shot all over the country all the time. That also goes to being able to understand the scene as it's unfolding. Unfortunately, the pros will also tell you that, too, is impossible, and they set up training scenarios to defeat your best appreciation repeatedly, all drawn from actual situations - where the pros got shot.
Get the training - but understand it will come from a Pro, who is certified and required to run toward the sound of gunfire. That's his duty calling, but you need to consider whether that is your responsibility at all. Do you have family, are they with you, will YOU be perceived as an accomplice? After all, the cop on the scene - or other CCW - can't know exactly what YOU are up to.
The recent LV Walmart incident has yet to be released on the reputedly extensive video that the company uses. Nonetheless, as a situation that anyone could find themselves in, it hold lessons to learn.
That's what you do when you decide to carry. Adequate practice will keep your skills in marksmanship up, so it will have an expense in ammo. But more importantly, study and practice in recognizing threats as they develop in a changing situation is where we all need a lot more training. We can't risk gaining experience, tho. Even the Pros get shot.