The shooter aspect is 'the successful brother' while the horror aspects come in as the 'failed prototype brother'!
F.E.A.R 3 is simply a solid shooter with weak horror elements. Horror games like Dead Space and especially Amnesia: the dark descent(which is far scarier then dead space) make this game look like a scary children book in terms of horror. I guess its expected, considering the gradual reduction of horror elements as the series progressed. Probably the reason for this is to appeal to a wider audience.
Everything is sound in terms of an FPS experience. Good variety of guns with some vehicle play. Not a very scary game. Some bits make you jump as a result of cheap horror tactics (i.e popping out at the screen). This game doesn't make much of an effort to 'get inside your head'.
I was also a bit annoyed by the timings of these 'scary events', you see, for the most part you need to be looking at the right direction at the right time, this wasn't always the case for me. (I was looking at scenery, checking behind me and looking for ammo).
The game has good pacing, with shooting sections and ambient bits broken up through the course of your play through. Guns sound good to shoot, and you feel the power as enemies are blown away. Controls are solid, though the initial interface when the game is loaded is a bit too console like. I think the graphics are great, not spectacular, but the definitely get the job done.
My score reflects the solid FPS experience, good story and graphics, decent AI and sound. The people that were expecting a horror game first, and shooter second, like F.E.A.R 1 will be bitterly disappointed. I, on the other hand, was happy with the game as I was expecting a more shooter oriented style then actual horror :).
Final recommendation:
Fans of FPS should definitely consider playing this game. Fans of the series horror qualities will be let down, but nonetheless pick up this game for its story and OK attempts at scaring you.