TrackIR is the kind of device that completely spoils you. Imagine playing a dogfighting sim, like IL-2 (amazing sim), and being able to pan your view around at will without fidgeting with a POV hat. It amplifies the movement of your head, so you can keep an eye on the monitor even if your avatar is looking straight back. In a game without radar, it's a godsend for tracking enemies and staying situationally aware.
It also works in Arma, but its usefulness is quite limited. It's nice for vehicles, or when you are sniping/camping and you want to glance around without readjusting your aim; but imagine if you are looking out for enemies, and your gun isn't on your screen when you spot one (TrackIR controls head movement, not body movement). It's more efficient to use mouselook.
The next DCS module will be the A-10 Thunderbolt II. It is due out in Q4 2009. They already did the A-10 in LoMac, but this sim will be much more detailed and realistic. After that, they're doing the AH-64A Apache (not the Longbow, sadly).
