Great additions to the FEAR series.
Extraction Point takes place right after the original game ends. It follows the Point Man in his continueing fight against Paxton Fettal and his replica soldiers, and Alma. I thought of this expansion as a great thing to play. It really blended the original FEAR and this one together. While this isnt a true sequel, it really felt like one. This is definatly the stronger of the two expansions.
Perseus Mandate is played from the PoV of another FEAR squad's sargeant. They are dispatched to fight ATC and Replica Solderis in their fight to stop the paranormal threat. While you are playing as a different person, you still have the slow-mo option, which really didnt make this from a different person's perspective. I believe that it would have been better to play it without the option to use slow-mo, just to see how it would feel.
As far as gameplay is, both games are very similar to the original. It is basically the same game, just with different objectives, some new scares, and some new weapons. Nothing really new here. Not that I am saying that the fact that it is like the original is a bad thing.
Presentation wise, Extraction Point really shines. While both have the classic FEAR feel (great action, heart-pounding horror, ect.) Extraction Point does a better job at showing this. The graphics are better looking and it looks more like the original than the other. Perseus Mandate lacks behind in very small ways however, its very similar.
----------THE BOTTOM LINE----------
FEAR Files is a great addition to your collection. It is very similar to the classic, which is not a bad thing really. It is a great addition to your video game collection, especially if you are an avid FEAR fan.