Like Old Bill Dibble, I'd have to put my experience with the Heritage Rough Rider at the top of the list. Exactly the same reasons as him too. Felt cheap, shot awful no matter what ammo I used. Was glad to trade it in.
The other for me is also a Bersa. I bought the Bersa Thunder CC as my first CCW gun. It bites, pinches, hurts to shoot and wore out the slide stop within 400 rounds. Never was able to make a load for it that made it comfortable for me to practice with. Like someone else said, it sits in the safe cause I just don't feel right selling it to some poor soul.