Wheel guns are real guns, S&W Military and Police compact...
Of the 2 choices, I'd say wheel guns are real guns,
.
Really, either firearm could protect you with proper care & ammunition selection. I'd lean towards the nickeled .38spl J frame over the PPK/S because it conceals well and will hold up better to grit, lint, dirt etc than the .380acp.
Either sidearm can get a CT lasergrip;
www.Crimsontrace.com . The Hogue line of grips are a great add-on too;
www.getgrips.com .
As for carry/protection loads, many shooters have had issues with JHPs & defense rounds in the PPK models,
. Pistolsmiths or custom work can improve the Walther PPK/PPK-S series.
If it were me, I'd sell both firearms and put the $$$ towards a new S&W MPcompact in .357sig or 9x19mm. You can get 2 free S&W magazines or a $50.00 rebate too,
www.SmithandWesson.com .
Other good carry models would include a Ruger LCR .357magnum or a CPO(pre-owned) SIG Sauer P239 DAK/SAS II in .357sig or 9mm.
The cheaper Ruger SRc 9mm could work for concealed carry but it's had mixed reviews and to my limited knowledge no US police agency uses the Ruger SR9 line. The SIG and M&P pistols are very popular with LE and citizens.