If you have a Bersa 380 of any type and you go after articles about it, the one word that pops up repeatedly is "Walther." The Walther PP/PPK predated the Bersa Thunder by several decades, but how do the guns actually compare. Let's take a look.
Both guns are .380ACP caliber although the Walther was originally designed as a .32ACP). Both have a similarly-sized 22LR little brother. Both are all metal frames with steel slides, no polymer here except in the grips. Both have an exposed hammer, a traditional double-action trigger mechanism, a single-column magazine that holds 6-7 rounds, and a fixed barrel, which also acts as the guide rod for the recoil spring. Both use a straight-blowback method of action.
Designed in 1929, the Walther PP/PPK is a marvel of classic German firearms engineering. Some five million of these guns have been made over the past 80+ years for military, law enforcement, and civilian use. During the 1950s, Manurhin in France made many of these guns and by the 1970s Smith and Wesson was making them under license (as the PPK/S) in the US. They are still in production and are a classic compact firearm. Heck even James Bond carried one for 35-years. Today's S&W version weighs in at 22.4-ounces is 6.1-inches long overall with a 3.3-inch barrel. It is slim at just 1.2-inches.
Designed in 1995, more than sixty years after the Walther, the Bersa Thunder 380 has the benefit of being inspired by its predecessor. Using a light aluminum alloy frame that reduces weight, it is about 3 ounces lighter but slightly longer at 6.6-inches and a width of 1.3-inches. Its chamber throat has a nearly straight-in feed angle, which means you can feed it almost any ammo reliably. Simple and effective, the Bersa is both rugged and utterly reliable.
Pluses and minuses
With all things being said, the guns are pretty well balanced in so much as ergonomic, accuracy, durability, and overall design. A slight nod goes to the Walther for fit and finish, especially of German made versions. This is counterbalanced by the Bersa's slightly more sleek profile. Some older Walthers have issues with feeding JHP defense rounds while Bersas seem ready to gobble any load. Bersa, through their importer Eagle Arms has a good lifetime (but nontransferable) warranty. In the trigger category, you would expect the Walther to be smoother but the Bersa actually takes the win in this marking as well, with both a lighter double action squeeze and a shorter reset.
The big difference between the two is cost. Typically, a brand new in the box Bersa has a cost less than the MSRP of $335 and used guns can often be found in the low $200s. Smith's MSRP for the Walther is $629 and even well used PPKs cannot be touched for less than $400. Many older WWII-era Walthers are collector's pieces with historic and monetary values so high that they are not wise to shoot. With that being said, the Bersa is by far the more affordable of the two. Likewise, if you carry a Walther in your car, home, or on your person and it gets lost, stolen, or seized, its less of a blow to your pocketbook.
No matter which you choose, they are both quality guns. The Bersa just seems to give you more bang for your buck.