Using the screenshots you provide, Killzone 2 has smoother features where as Gears or War 2 has better lighting. Considering that GeoW2 is releasing this year and Killzone 2 next year then GeoW2 looks better as it is further along in the dev stage but i do expect Killzone 2 to look better by the time of its release.
End of 2014 Hardware Predictions (03/03/14)
PlayStation 4: 12-15million
Xbox One: 7-10 million
Wii U: 8-9 million (Changed 01/04/2014 from 7-9 --> 8-9 million)







