The problem with FFs, though, is that while they don't need a target lock to fire, they may not be going for your intended target.
When I play, I often set up 2 launchers with IRs, and use a little bit of fancy shooting to engage 2 targets at once. Using the joystick controls for missiles, you toggle off a pair of missiles with one button press to engage one target (which will kill a Talon entirely, and put a hurt on a Demon; don't recall their effect on other ships, off the top of my head), and use guns on another, aiming manually. Especially in the early missions before you max out your starting Tarsus, this can be a lifesaver. Even if the missiles don't kill the targeted ship, they'll be too busy dodging the missiles to target you.
(This is also how you can get the Steltek drone off your back before your gun gets charged so you can harm it. Even if the missile can't scratch the shields on the drone, it'll still go into evasive maneuvers, usually long enough for you to make it to the next jump point and, as the cliche goes, get the hell out of Dodge.)