Headrest is amazing! I have to give props to both Atlas Headrest and Crandall Office both for the amazing work they put into this headrest!
The headrest is fully adjustable (horizontal and vertical) within a very wide range of movement and a very simple to use mechanism. Assembly was straightforward and easy to perform with all neccesssary tools provided with the product. The cushion material is very comfortable.
I tend to use headrests as a means to rest my head when I lean back all the way in the chair and not when I am sitting up in an active work position (for reference, the steelcase series 2 headrest was perfect for me), so I was cautious if this headrest would suit my needs since most office chair headrests are more aggressively desgined than I would like. I am glad to say that the adjustability range of the headrest allows for both use cases to be satsified. Currently 25 days in with no issues to report!
For reference, I am just under 5'10" and my shoulders rest just over the back of the chair sitting properly (~1 inch or so).