Just completed this, thoughts below:
+Good graphics/performance combo, 90+ fps nearly the whole way through while looking decent. No idea what people are smoking if they think the original FEAR is as good visually, the environments in F3AR are miles better.
+Better variety of locations than previous games in the series
+Not as 'scary' as the earlier games
+Lots of gory violence
-Storyline is pretty dull
-Can't save your game and checkpoints are unevenly spaced
-Very shoddy continuity i.e. on the bridge level I got out of my mech as it was about to explode, then continued far enough on foot to trigger a checkpoint. This then rendered the level basically uncompletable, I managed to take out 3 mechs on foot but finally came up against two choppers at once and no way of getting rocket ammo because the enemies with rocket launchers were high up in inaccessible areas. Because there is no save or even ability to choose checkpoints this meant I had to restart the level losing about half an hour of gameplay
-Pretty short game @ 6-7hrs, although I haven't played as Fettel.
-Combat is a step down from the original FEAR, I'd say in terms of feel it is closest to Soldier of Fortune 3
-Managed to get stuck in a corner at one point when moving behind cover and reloading
-Weapons are handled badly, not only can you only carry two but it also strips you of weapons in between levels.... yes what a great idea when confronting a team of elite mercenaries, I'll ditch my lightning gun and replace it with a pistol for no apparent reason! Ammo limits are pretty low as well although they do increase as you level up.
Overall it feels like the series has run its course, I wouldn't recommend this game unless you are a die-hard fan of the franchise. On a more positive note I didn't experience the problems some have mentioned, in the current version if you disable motion blur, Ambient Occlusion, Auto-aim, mouse smoothing and Controller, then set sensitivity to minimum and increase the FOV to maximum it plays OK.