Track IR 3 pro has a refresh rate of 120 fps
Track IR 3 has a refresh rate of 80 fps
Track IR 2 has a refresh rate of 100 fps
The difference in 2 and 3 are that 3 has 67% more resolution and improved optical performance that allows it to work in direct sunlight. With track IR 2 I just pulled the shades down. I didn’t have to sit in the dark it just I have a window that is directly behind my monitor. It’s sunny in Florida

. I just pulled the shade and the curtain and it was fine.
I have both track IR 2 and 3 pro and there is no difference in frame rate while panning that I can tell. Both are smooth. I, like Blauk, don’t turn my head but lean side to side.
I certainly never got nauseous playing any game that has native support (enhanced mode). Neck ache? Even turning your had its like 2 to 5 degrees depending on how far you sit from the device. Just sit comfortably and center it. No need to sit like stiff zombie with a neck brace on.
My frame rates in Il2 are high (60 or so excellent settings) but they aren’t above 100 / 120 fps. So if your game FPS is faster then track IR's refresh rate then wow you got a kick arse system.
Mars,
Ah doesn’t have native support so you just have a "mouse on your head". There's huge difference in enhanced mode. Move the mouse fast in Ah2 and there is blurring. If you have FB/AEP give a go there. That’s why losta folks are bugging HTC about native support, there's a world of difference.