Well, I don't have any experience with the Thunder 380, but I do own a Thunder 45 that I have close to 500 rounds through, without any problems. It's an economical, well built firearm in my opinion. If you're gonna carry it for self defense, you may want to look at the Bersa Thunder 9...almost same size and weight...better caliber for self defense...cost for ammo usually runs less, believe it or not.
I have owned both the Bersa .45 and the .380. Neither one is particularly fun to shoot,but they are both totally reliable. The ejection pattern on the .45 used to occasionally put a piece of hot brass right in the middle of my forehead,but thats a small price to pay for a reliable shooter. I still carry the little Bersa .380 and like it better than my Walther.
I bought my first Bersa back in 1988 on a whim. If I remember correctly it was like 175.00. I shot the heck out of that gun!!! My wife got her CCW a few years ago andwe bought her a new Bersa thunder 380 and she loves it! never had a problem. As for the 9mm, 40 s&w or the 45 acp I can not comment on them. I am thinking about getting one of the 9mm's and trying it out. Dave