I use this headphone holder for two headphones, and the little slots on the end of the arm keeps the cables from drooping. It feels solid and has enough room for even the biggest headphones.
The clamp has slots on every side so you can clamp it on anything in pretty much any orientation and still get the headphone arm horizontal.
There's not really anything not to like about it, except that I feel that the appropriate price should be more around 16 EUR for such a small accessory.