Bersas haven't been adopted (or, to the best of my knowledge, even tested) by any major military or law enforcement agency. This means that objective, easily accessible test results don't exist. Thus, their short- and long-term reliability and durability are in question.
I know that they've been tested by gun rags, but gun rag "tests" seldom expend more than a couple of hundred rounds, and tend to gloss over any failures anyway.
And I know lots of people on the internet post about their excellent Bersas. But once again, we almost invariably see opinions based on low round counts, usually just a couple hundred rounds. I think this may be partially because serious shooters who expend lots of ammo are generally attracted to guns with longer and deeper track records than Bersa can currently produce.
While Bersas may indeed be excellent, long lived, totally reliable pistols, I haven't seen anything that objectively establishes such. I can, however, easily access test results with multiple sample guns firing thousands (or tens of thousands) of rounds with Beretta, Glock, SIG, HK, and S&W, for example.
I'm not saying Bersas are bad pistols at all - I know several people who are very pleased with their Bersa .380s. But I think this is why you see "doubt" about them. When someone takes thirty randomly selected Bersas and puts 10,000 rounds through each of them, then reports mean rounds between failure, number of broken parts if any, and accuracy before and after...well, then I will start taking them seriously as service pistols (assuming they survive the test).
And I think I have a reasonable idea of how to shoot, and what good shooting looks like. :mrgreen: