Ya know, IMO, Doom3 may be better than FEAR, minus the AI dept. FEAR is so horror cliche-ridden (I'm sort of a horror film buff), and for some reason at the time I played the game it felt so much like a Doom3 wannabe. I don't like Doom3 a lot per se, but I thought the crazed-gothic-dark-shit-loving folks at id really nailed the look and f-ed up atmosphere there. Some of the guys at id are totally into that kind of atmosphere as can obviously be seen in like all of their games. Doom3 really got me jumpy me when I played it alone in the dark, but FEAR wasn't really as gripping in that way. Probably partly because it came after Doom3, I suppose.
But, FEAR has awesome AI for sure. Too bad the game just gets horribly old. The best parts IMO are the beginning when things are fresh for you, and the end when it gets pretty darned cool. But there's a lot of "scary offices" nonsense to run through in the meantime and that was really quite boring.
It also definitely runs worse than Doom3 engine and doesn't look all that great IMO. It's decent though.
I thought the fighting moves were really cool. Kinda tricky to pull off tho.
I'd definitely give it a rent if you haven't played it before.