Apart from the hyper reflexes and hyer accuracy of the AI in GR1 I though it was really good. Some great set battles that I still remember.
GRAW I couldn't run on my P4 3Ghz, 1GB, 6800GS. It was a slide show even at low res and detail. I'll have a (945) 3.4 Dual Core, 1GB RAM, 7900GS soon and I'll try that. but I expect I'll have to drop the detail and res, and need more ram to get decent framerates.
The game "The Regiment" is a decent blast and is especially good when you're stuck for time. Sniper elite is more lightweight but fun. My fav's are still (apart from GR1) Operation Flashpoint, and Hidden & Dangerous. There aren't that many decent tactical FPS unfortunately.
Most are too gamey.