I recently read in a post that the PPK/S has significant felt recoil (when compared to other similar guns) and that after 100 rounds or so the poster's hands were tired and sore. While I make no claim to being a tough guy, I'm obviously tougher than that guy.
Yes, the first time I fired my ppk/s I did have a small blister in the web of my hand from the beaver tail after about 100 rounds or so but, I blame this on having never fired the gun before; with a good grip on the pistol that won't happen. So small in fact that I didn’t even notice it until I was cleaning the gun and got some bore scrubber in it and it burned a little. I've never had a problem since, and I regularly put 100+ rounds through it at the range; and we go a lot (seriously, a lot).