S.T.A.L.K.E.R.: Clear Sky - Review @ RealGamer

Another good score for STALKER: Clear Sky with RealGamer's review awarding 8.2/10, despite the majority of paragraphs listing a litany of design issues and problems.  At the end of the day, the author enjoyed the atmosphere and the game not "playing fair".  On the random factional fights:

But as a gameplay mechanic, it's disappointingly one-dimensional. Instead of opening doors for all manner of tactical thinking and careful strategies, it creates a rather tedious and repetitive 'obvious route' to victory. That is, to sit for a while away from your current objective, and wait for the inevitable support to arrive, letting the friendly AI do most of the shooting and allowing you to conserve resources. Admittedly, you're likely to be picked off by a sniper or mauled by a wild boar on a few occasions while using this tactic, but it's a hell of a lot more forgiving than the fiendishly difficult fire-fights in Clear Sky. Enemy AI is hugely impressive, but even on the easiest of difficulty settings, each close-quarters battle is likely to require a few goes and a huge amount of quick saves to end in success. It's not even a case of trial and error, due to the semi-random nature of the game.