I had a stainless Walther PPKs when they were still being imported by Inter Arms, so I'll speak to that:
1) overall, I always thought it was too much gun (size and weight) for the payload. As a direct comparison, I look at the Air Weight J frame in .38 Special. Even shooting the 148gr. wadcutters you will be delivering a bigger, heavier, faster moving bullet than the .380ACP. (The same argument could also be made for the Model 432 in .32H&R Magnum.)
2) I have "normal" sized hands (size 7.5 surgical glove, Medium sized work gloves) and I always got "bitten" by the slide. I never experienced slide bite from a 1911, or a Hi-Power, or even an Astra Constable (Spanish made PPKs clone). I'm not such a wuss that slide bite would scare me, but I always worried about it causing a malfunction to the weapon.
3) Finally, reliability was an issue, or perhaps, I should actually should say confidence, rather than reliability in that I never recall a failure to fire, failure to feed, or failure to extract, but the Walther did go full auto on me one time at the range. I bought the Walther new, and it had never received any gunsmithing outside of the factory, and the factory repaired it without any charge to me, but still, I was always a little leery of it afterwards.
I eventually traded it in for one of the West German Police H&K P7 PSPs that had been on my grail list for many, many years.
Best of luck,
Dave