If you are not using a headphones for audio, the hat clip has its appeal. The later revisions of the hat clip have much more curved reflectors to allow tracking of more extreme angles. But every time I try to go back to the hat clip, I find the tracking ability is so much degraded by ambient light and worse yet, my glasses, that I very quickly go back to using headphones and the pro clip.
I used TrackIR 3 for quite a long time before getting the TrackIR 4 Pro with the pro clip, so I know you can get it to work well enough. But the pro clip with its active source, provides a much better target.
To be fair, Oculus Rift is a much better value. You get a hell of a lot more for $350-$400 than what you get buying TrackIR 5 Pro. The precision/consistency of Oculus Rift tracking puts TrackIR to shame. If Track IR kept the same price but went to dual sensors to get the precision/consistency of the Oculus Rift, it would be a much better product. With TrackIR, I always have to have a button on the HOTAS mapped for re-centering since it will drift whenever I exceed its effective tracking angles. Oculus Rift usually needs one calibration when you first start playing, then stays perfectly aligned.
I like flying with VR. The 1:1 tracking is incredibly immersive, but the low resolution kills me. So I alternate as required by the sim and mission I am flying. The TrackIR annoys me with the constant need to be re-centered and the jerkiness resulting from having to use response curves and/or deadband zones to make up for the need to allow 180 degree horizontal look angles and 90+ degree vertical angles without having your eyes look past the monitor. But it is very hard to go back to VR after seeing normal 2d graphics quality.
