I can't tell if you mean the G43 or the PPSh. The Conscript PPSh movement penalty is about average, the G43's is better than other semi-autos and even SMG's.
It was on response of the SVT vs PPSH comparison. Thing is i waited to reply since i found a game.
As for the PG G43, they do less DPS at every range compared to the StG's they replace, I'm not sure why you would want them!
They have almost double DPS at far range. In comparison, a bit better than a Kar. Nevertheless theres little point on upgrading them unless you float munition, you want "cool" G43 and you use nonstop interrogation.