I've owned the cosmos for about two weeks now and have been loving it. This is my first venture into VR so I don't have anything to compare to except what reviewers say. I bought the headset despite the bad reviews and have been pleasantly surprised by the performance and picture quality.
The only thing that is an issue is when one controller is occluding the other, the occluded controller will sometimes move sporadically or snap into position once the tracking picks it up again. Also, moving the controller out of view of the cameras, such as behind the head, will do some weird things. Neither situation has posed a problem for any games I've been playing (half life: alyx, witching tower, skyrim VR).
Overall the tracking has been fine for me but I always welcome improvements!