I agree. I am not sure to what quality control issues the OP is referring. There was a recall, but all of the guns sent in were fixed. The Walther people licensed production to S&W and sold the S&W version to its European customers, so I don't think Walther had any issue with QC on the S&W-produced Walthers.
For that matter, the Gadsden, Alabama produced Interarms pistols were very good also, and yet you still read of people who think those had problems. As a matter of fact, of all of the things Sam Cummings did (and he did quite a bit), perhaps the best thing he ever did was to ink the deal with Walther to make real PPK and TPH pistols in the US. Were it not for Mr. Cummings, we would be stuck with the PPK/S. I guess some people like those, but no one in my circle of shooting friends.
When the West Germans replaced their PPs in the mid-70s (the pistol trials that resulted in the P5, P6 and P7 pistols, from Walther, SIG-Sauer and HK, respectively), the typical German or French produced (remember they were also made by Manurhin) pistols were routinely unable to go through one box of 50 rounds without a malfunction.
The purists over at the Walther forum seem to think that any PPK not produced at Zella-Mehlis or at least at Ulm-Do (which means, "Ulm, on the Donau (Danube) River") and which were not personally tested by a high party official are simply not up to the grand name of the Walther house. However, I think Walther does not license junk, and the Interarms and S&W pistols are very nice. Frankly, it is nice that we can buy them at all, since the PPK does not "make points" and cannot be imported under the 1968 Gun Control Act. I feel so much safer, don't you?
There is really nothing wrong with S&W-produced Walther PPK and PPK/S pistols, apart from the fact that there are lighter pistols of the same size in 9mm, a more effective caliber.
It is really irrelevant, as production of the PPK and PPK/S is moving to the Walther Arms and Umarex facilities in Fort Smith, Arkansas. Thus, the next we will see is the internet lighting up with how great the Gadsden and Springfield PPK pistols are compared to the "junk" they are turning out in Arkansas. One thing is for sure, if someone can run a product down, they will do so louder and longer on the internet than was ever possible in the past.
By the way, I am sure the Fort Smith PPK pistols will be just fine.