Due to frame design PPK/S is a little heavier and easier to grip thus in .380 might be a little more controllable than a PPK in .380. That said the PPK is a little more compact and it is the one Bond carried (but only in .32)
It has been my personal experience that 7.65 PPKs are pleasant and reliable, while .380s are not.
It feels like the slide is clanging on the frame at every shot in the .380, and it is distinctly unpleasant to shoot.
(Before I get any accusations of wussiness, I'd rather shoot magnums in my 340 than .380s in a Walther!)
Balistically there is no huge disadvantage with the .32.
I would agree with moon (if I may call you that, or if you prefer: halfmoonclip). I have a PPK in .32 and one in .380--I dunno, maybe I'm a wimp, but I really notice the .380. Cor-Bon+P's are not very pleasant in .380 PPK! Also, Walther-bite is easy to avoid in .32, but for me it's a given in .380. I also agree mit Herr Walther--it's very easy to shoot an impressive group mit der 7,65mm, but it takes a little more concentration with 9mmK in my wimpoid experience.