I’m more active in the gun realm these days than Knives now that we are back in the states. I regularly interact with some of the top trainers in the industry, owners of gun companies and gear seller and manufacturers hell even the VP of Magpul on occasion.
I say that because I have a large pool of people to pull info from and can say that when they post up data on firearms used in classes and those with the highest fail rates, Beretta seldom even makes the list of a firearm used unless it’s a newer model. Even in the military they were reportedly pretty problem prone, but there wasn’t as much to choose from 20 years ago due to Contracting laws. Now you have companies like Glock, FN, etc who have opened up factories in the US to allow them to compete in military solicitations since many require items to be produced in the US.
Glock and Sig are the most overwhelmingly popular, with the 2011 STI and offshoots becoming much more popular since the new mags have drastically increased reliability, S&W and HK are also popular in certain models. Springfield is normally listed as the most failure prone in high round count classes. CZ has some following, but are moving more to competition. Sig is known to use early adopters as beta testers. Glock is the Honda Civic of the Gun world.
but everyone has their preferences. I currently run an STI Staccato P and DVCP and man do they shoot! Here is a target of 2 17 round mags at 21 and 33 feet. I also have a HK VP9 that I really like as well as my backup. My wife is a Glocker