I've used a track IR for about 3 years now, and absolutely would hate flying without it. It's true, the Immersion factor is extraordinary and makes the game a lot more realistic and exciting.
You'll want to spend a good 2-3 hours with the configuration setup to get a setup that suits how you play and move your head. It's a very personalized device. A couple tips though....
Setup a custom setting and start it out medium aggressive in the movement, and slowly creep it up so that turning your head just a little, gets you a lot. But not so much that you can't accurately follow a contact. A good way to test this out is to set it up, and go into the training arena and just follow the other players in the area to make sure you can track them. Look for "stutters", if your tracking a contact and the screen freezes just momentarily, then it's possible that the LED's are being blocked by a headset cable, possibly the mic boom, or your little receiver mounted on your monitor needs adjusting.
Secondly, leave your HAT switch views engaged. As mentioned the HAT switch views are MUCH quicker, and I use them primarily for the forward view, and for the rear view. If I'm following a contact, and about to fire, I'll press forward on the HAT switch to override the TrackIR and it keeps my reticle centered on the target while I fire. That way it can't drift if my head isn't steady. I used this a lot in the beginning, but rarely use it now because my head is much more steady, I'm used to the TrackIR, and know where my center position is at. The other time I use the HAT for views is the rear view. I pull back on the HAT switch, i'll be looking at my seat, and I can pan my head left/right to look behind the seat at contacts coming up behind me. It's super quick and easy to do. I also have a button on my joystick that "Centers" the forward view. That way if I shift, or get out of whack I just quickly center my view and I'm back in business. It's also good for shooting, I'll center the view right before I fire as I'm coming up on a contact.
Third, It's awesome that you can have 6 Degrees of Freedom to look around your cockpit and out into the world. However, I've found that having the head "tilt" engaged made me quite disoriented. So I disabled it and never looked back. There's not any really great reason to need it, and it just made things more awkward in the beginning. Being able to shift up/down, left/right, in/out is plenty of movement to see everything you need, so the tilt isn't necessary.
Again, it's great fun once you've set it up, and configured it for your personal style and movement. Get in the training arena and just fly around. Have some fun with it looking out the windows and tracking bad guys. It took 3-4 weeks to completely get used to, so put in the time and expect to be worse than you were. It's just like adjusting to a new joystick, or rudder pedals. But it's worth the time in my opinion.
Hope this helps and if you have questions, feel free to ask.
