GSC is my favorite developer as is Valve and ED.
GSC tried to create an AI engine first and my opinion is that is what is missing in PC gaming and that is were PC gaming has to be improved and not Physx(crap). That is what will make PC gaming strong. They tried to innovate and take risks, they create an immersive atmosphere. I really can't wait of what they will develop in the future.
With CoP they improve in a lot of things. Better AI, improve gun ballistics (bullets don't hit a wall any more, they fall to the ground naturally), imersive awesome quest system with choices and consequences, optimizations for better performance.... and a lot more...