Hi Adguy,
In the past couple of years I have written a book on the Bersa Thunder 9 Pro here, and I have also owned one of the UC versions. You can prolly find some pretty extensive reports I gave on the gun in the site's archives a couple of years back. In total, I have owned three of these guns, two full size and a UC, got them all up around 700 rounds total, and never had a malfunction with any of them, even with +P ammunition. The T9 Pro full size is my house gun and sometimes even my carry gun.
I basically do not like cut down service pistols, preferring the heft and pointability of the full size service versions. But I liked the UC better than any cut down service pistol I have ever handled and found its recoil to be very close to that of the full size pistol it was developed from. It also had an excellent trigger and a 13 round magazine, which is as much as a stock BHP, and it handled very well. I sold it to a friend who isn't infected with my bias about cut down service pistols, and he has shot the heck out of it and likes it very much. In my experience, the Bersa Thunder 9 Pro, as it comes from the factory, is a reliable firearm that generates few complaints on the internet gun forums, and enjoys a very good reputation with its owners. If gun forum comments are a reliable indicator, I'd say the UC is a pretty hot seller.
As for textbook formidability, the Bersa you are discussing is the more formidable defensive piece of the two because of its more powerful cartridge and larger ammunition supply. But the only criteria for selection of a defensive piece is shootability in your hands. The Bersa ceases to be the more formidable of the two if you can shoot the Beretta better. So my recommendation would be to buy the one you can shoot best and heck with anything else. A hit with a properly placed .380 bullet is a lot better than a miss with a 9mm, but only you can decide which gun will be the better performer in your hands.
JayPee