I've had two of the PC9s, one with ghost ring sights and the other with standard irons. I had the same Weigand rail articap pictured, and it worked fine with a Millett red dot setup.
I would disagree with articap that the trigger on these rifles are generally not heavy. Having owned two of them, both with heavy triggers, I'd say articap got the peach out of a bunch of lemons when it comes to the trigger. It's also a heavy rifle for the cartridge it fires. However, this works for it when it comes to recoil (there's hardly any) and it's relatively compact.
I couldn't make either of mine malfunction, even when I accidentally inserted a CZ 14-round 9mm pistol magazine into one of them! The Mecgar mags worked fine for mine, including the 20-round version. One of them was more accurate than the other, but not much more.
jm