I LOVED the first one, best game in a few years in fact! I had no bugs what so ever and thoroughly enjoyed it.
Bought Clear Skies on release day, got it home and installed it. The bugs are un real.
It crashes frequently and the graphics are terrible (I have everything maxed on 1440x900) and the guns look aweful, so does the scenery. So I just stopped playing it and I'm just waiting for a bucket load of updates before I try again.
It's up to patch 5 at the moment and I have installed them all, but I have yet to try the game again.
My stalker is HACKED and runs well No bugs For 11 Hours