After using FreeTrack with a MS Life Cam a few years ago, then moving to FaceTracknoIR it was a big difference. The fact that I didnt have to use batteries and a homemade setup, just my head was cool.
After getting a PS eye, and going from 15-21 fps to a constant 30fps I could tell a difference. For some reason, I could not get the PS eye over 30fps even by adding the cleye.config file. I ended up buying TrackIR 4 pro off craigslist. Finally I am happy.
My take on this whole thing...
Freetrack - Good stuff with a PS3 eye running a higher dps. Pain in the but to get it set up the rght way. It seems (to me) like a constant battle to get it centered, and if you have to step away from the game, well back to re-centering it, and tweaking it. Batteries in my LED setups was a constant battle with long play times in IL2. Replacing LED lights was getting annyoing. Its free which is good, but too much tweaking. Worse part, a bit of jitter here and there.
Facetracknoir - Again good with a PS eye (even better I assume when you can get over 30fps). I loved the fact you dont need anything on your head. The problem was again tweaking and setups. You have to make sure the lighting is just right. Not a problem when I played at night. But on a weekend afternoon, ambient light was screwing me. After a week of constant setting tweaking, I was getting frustrated. Changing lights, adjusting curves, adjusting the physical cam, and the filtering. It was getting to be more tweaking than actually playing some il2. Worse part, jittery, and jumpy.
TrackIR - So I bought TrackIR4. Not the latest version, I know, but I still cant drop 150+ on it. It only has the hat clip not trackclip pro. I was sckeptical on how it will work compared to the others. I installed the latest driver, set up the tiny reciever, and put on the hat. Fired it up. It was almost dead center, but it hit F12 once to get true center. Loaded il2, and it worked. No tweaking, no cam placement issues, no adjusting even one setting. It just worked out of the box. While playing I had to get up, walk away from the cam, and was prepared to re-center and re-calibrate when I sat back down. Nope, no need. I was right back into the action without having to do a thing. I can play in the dark, in the light, and no problems. The best part....it is smooooooth as silk.
So to wrap up. I love the face Freetrack and Facetracknoir are out there. I hope they can continue to improve and actually market their products the same way TrackIR does. TrackIR is way too expensive for what it does and they NEED some real competition. But, as of now, nothing can compare.