I can't fly without it anymore. I even stopped flying other sims that don't have that level of TIR implementation that AH does (most notably Il2). The biggest plus of course is immersion. I have no views mapped anymore on my stick since I got my TIR.
If you are neck twisting, your setup is wrong.
You can tweak TIR settings by a huge amount. Two different settings from two different players can be very different. Deadband, movement agressiveness, disabling of certain axis, and so on.
If you get an TIR, it's very important do fiddle with all that settings for some time, until you find a confortable setup. It took me about a week to getting used to it and to find the right settings for me. Again, what is considered a good setup by one player would drive the other one mad. For example many pilots do have a "forward view" button that whil fix their view on the gunsight, they press it when abut to shoot - I on the other hand never fix my view or disengage TIR, I take full advantage of the reflecting gunsights.
I found TIR to be most advantageous in tight dogfights with alot of scissors/barrel rolls, having constantly my eyes on the enmy without ever losing track of my view's position relative to the planes alignment.
Another very important bonus: the thick cockpit frames of the 109's do not bother you that much anymore when your head/view is freely floating inside the cockpit. Just lean a bit to the side.
In most planes, 6 views are no real problem. I just turn my head a bit and lean over. The advantage is that I don't have a single rear view, I can quickly alternat looking left or right around the headrest.
There is one issue however: In most blue planes, particulary in the F4U's the rear views are somewhat porked. See
http://bbs.hitechcreations.com/smf/index.php/topic,232289.0.htmlIts is
worth the 179? That's a difficult question.. depends on your budget
It's not a absolutely necessary item (like a joystick) but it's fun. But you may check out Free Track too.. seems to me it's working quite good.