Hello. I reckon I missed this thread before and just read through it a moment ago.
I would assume that some dealers may indeed talk down anything that they happen not to be selling at the moment, while others may believe that unless the gunmaker's name is household common, the firearm must be second-rate, have "bad metal" or whatever.
I might offer an opinion at this point and it is only that as I cannot back it up with any hard, cold facts:
I believe that the Bersa Thunder 380 remains a "best buy" in midsize 380 autopistols.
I can vouch for the following:
I lost my ammo consumption notes on my sole Thunder 380, but it's digested something like 3000 rounds, most was factory 95-gr. FMJ as well as various maker's JHP's. I do not recall how many rounds I fired at each range session but would guess not more than 150 before finishing up or moving to another firearm. In any event, I never did fire round after round and box after box of ammunition to see how dirty the little gun would have to get before it began to get sluggish or malfunction; I'm not too concerned, either. The little gun's run fine for me each and every time I've shot it. My total number of malfunction is exactly zero.
I cannot intelligently comment on the scientific aspects of the pistol's metallurgy or construction and mine may be about to self-destruct on the very next shot...but somehow I doubt it.
As I've said many times, I may not be devotee of the 380 ACP round, but I am a fan of several of the pistols chambered for it. That said, I have two friends still in law enforcement who have close-and-personal experiences with 380 pistols. One was shot through the chest and arm (bullet entered at an angle) with FMJ. Luckily nothing of importance and no bone was hit. He returned fire but missed before his legs "turned to jelly" and he fell. He recovered fully and remains one of the most lucky men I've ever known.

Not the most expensive to be sure, this Bersa Thunder 380 auto remains a favorite of mine for BUG use on rare occassions. Most of the time, it is shot for fun at the range. I simply enjoy shooting it and these days I rate "fun" as a high-priority item.
The other was forced to shoot a felon trying to him him. The felon got off 4 quick but inaccurate shots with a Bersa Thunder before my buddy was able to solve the matter with two .223 rounds to the felon's head. (He told me that he still "liked" my Thunder 380 and that it is never a gun's fault that it's misused by criminals. Like all of my friends, he fully supports the Second Amendment and likes the honest citizen to be armed, but that's another topic...) While I've seen the 380 round come up a little short on penetration in some instances, in others it has done more than I ever expected. For example, it decked a full-grown drunk male when a 95-gr. FMJ broke his femur! I do not recall which leg or the brand of ammunition.
I know of a couple of other folks shooting Bersa Thunders and while neither shoots cases of ammo through their pistols, they do shoot them frequently and continue to report on the pistols in glowing terms. A man and wife recently qualified in a CHL course I taught using their Bersa 380's. Neither had any malfunctions and I do not recall seeing any with the several Bersa Thunder's I've seen come through the Texas Concealed Handgun Qualifications that I've had a part in for well over a decade.
Though I seldom carry them, I do own several 380-caliber pistols. While I like each for some specific reason, the one I find myself toting most often when carrying an extra gun for some reason is my Bersa 380 Thunder.
I do voice one complaint, however: Why in the world didn't I go back and get another one (or two; I operate on the "pair and a spare" approach to firearms I like when possible) when I had the chance? (While I've not seen or read of any problems with the gun's lock system, I prefer my firearms without.)
I have heard of a couple of officers with newer Bersa's having feeding problems but I know no more than that. I suspect that the magazines are probably the root of the problem. Other current owners I've seen report no problems.
Best and good shooting.