I assume we're talking new
guns here. If that's the case, I'd go with the Beretta.
The Walther PPK is a fine design, and, as manufactured in Germany and France, was a nicely made and reliable firearm. BUT
.....the currently made U.S. production ones have had a lot
As a native Mainer, it pains me to say this, but the U.S.-made PPKs, built in Houlton, Maine, seem to be cobbled together by a bunch of unemployed Aroostook County potato farmer's wives......who may be great at picking potatos, but know nothing about making pistols.
Go with the Beretta.