After seriously playing, I really came to enjoy the detail in GRAW that immersed me. I haven't seen many explosions like this before(i don't use the physix card either). When I blew up a car, not only did the car release a lot of shrapnel/smoke but these hanging pieces from another structure got hit too, causing a few pieces to dangle off. As they were dangling, you could see the real time shadow casting on the ground and then the pieces finally fell off.
Also, if you shoot through the trees, the leaves move.
The implementation of HDR is actually worth mentioning in some areas. I was looking at a striped metal business door and the the lighting would reflect off each shingle edge ilike when the sun bounces off metal and gives off a blinding glare into your eye.
Yes, the performance could improve, and the graphics are not perfect, but it is nevertheless a very dramatic atmosphere. I am used to playing Rainbow Six's graphics(with a noticeable lack of technology shift generally) and still loving it. This just makes it better.