I don't know, I don't have a big problem putting 100 rounds through my 14 ounce P11 in 9mm. I don't have a P3AT......YET. Recoil ain't going to be one of my considerations in buying it, though. It'll be for deep concealment. I probably won't carry it all that much, just when I can't practially carry my P11, which ain't often. The P11 isn't physically as large or heavy as a PPK, don't think.
What I'm trying to say is, if you can carry a PPK, you can carry a more effective caliber easier. But, the P3AT has a real attribute, its tiny size. I have situations from time to time where I can't even carry the P11. In those times, I need a SMALLER gun, not a givver, heavier gun in a less effective caliber. The PPKs are just as effective as they ever were, but they've been eclipsed in CCW application by newer designs. If you don't like the PF9 or P11, there are Kahrs, the Taurus PT111, and I think even the G26 is smaller, or just as small as the PPK.