Frustratingly good!!!
-Athlon 64 X2 4200 @ 2.2ghz
-ASUS M2N4 sli
-2gb Corsair DDR2 667mhz
-Nvidia 7600gt 256mb
As you can see its a pretty low to mid spec but was playable. The overall look of the game was amazing with stunning visuals of Vegas and its casinos. The character visuals are good but the terrorists are pretty generic. The gameplay is fantastic and I still have yet to play a game with better team tactical control as this. I used an Xbox 360 controller with this game and found it much easier. The storyline in the game is very good and it is very easy to get engaged in it completely. There are some major twists in this story (I won't spoil them tho!) and this really helps to keep you engaged.
The multiplayer aspect of R6V is amazing and again it is quite easy to get distracted by this instead of playing through the difficult campaign.
Overall I would say that it is a fantastic game with a brilliant story (frustrating ending!!!) and gameplay that I really enjoyed and continue to play even over a year later.