For those of you that have/shot both.
I own both and think they are both awesome guns. I got the PC9 first because it too uses Glock mags and it is near impossible to get an S2K in 9, especially G19 which is what I was holding out for. I am not asking any of us fan boys/girls which is better. They both have advantages in their own ways, and other than being portable PCCs, they both have their place for different needs.
One thing that will be interesting is when Magpul finally releases their new Backpacker stock for the PC9. That will bring the two much closer in terms of portability. The PC9 does have more limited space on the rail, but the rail on the PC9 is much more solid that the molded plastic rail of the S2K and the overall build quality is much better. Very different guns.
What surprises me is the recoil. I find that even though the STOCK PC9 is a heavier, more robust weapon, my full MCARBO rebuild S2Ks with all the recoil dampening gear have less retort that the PC9, even the 40. I’m thinking that is a testament to the fantastic products MCARBO has made for the S2K as opposed to some inherent quality of the guns.
I have bought all the MCARBO upgrades for The PC9 but have yet to install them. It will be interesting to see how they compare once installed. I’m waiting for Magpul to release the stock to do it all at the same time.