I find that FF in any current fps games are highly un-true to real life.
This irony is truelly due to the lack of sensory perception provided by the computer; we don't have preferal vision, we don't necessarily have hardware to provide 3d sound, we DON'T necessarily have decent communication method (ie talking, signalling to teammates)
many times i was firing only for someone to start charging at the healthy, angry, rampaging tyrent and walk right into my line of plasma (bahhhhh)
while more skilled player might say i'm just being a noob (which i really am lol), FF really takes away from what true reality would be like, which is ironic to the purpose of FF. So since most of our sensory perception gets eliminated down to primary vision and limited sound and almost no communication due largely to the limitation of the hardware/software, i think it's only fair to somehow compromise.
it's true that a lot of players, like myself, do abuse the lack of FF from time to time. but i think FF really only favores alien too much as well. other shooter games, such as counter strike, both team gets taxed by FF, but in this game, only human truely gets taxed while aliens doesn't. This seems to offset the balance of the game.
err... so... after lengthy blabbering, I for one is against FF in this game unless somehow it effects both team in fair manner (i don't even know how this can be done since it's hard to ff a melee attack accidentally), as well as there are some way to implement better sensory perception for the player to be more aware of the surrounding. (at least something can be improved for communication, i'm sure)