The Poseidon is a comfortable headphone to wear and is less fatiguing to the ear. It is padded well with a velor ear cushion. That makes it well breathable and prevents sweat. I use this as computer audio accessory.
This headphone leans more towards the upper frequences with less emphasis on bass. However the available bass is snappy instead of being muddled. The headphones tend to be a bit muddled in the lower mid frequency range when new. But as it wears in, the lower mid frequencies get well detailed especially for male vocals. There is more air on top. I have not experienced any fatiguing sibilance though. The music listening is not relaxed but edges towards more citical detail and wider sound stage. Though it is not a class leader in its budget class like the Senheiser HD 600S.
My main grouse with headphone is the creaking of the slider adjust mechanism on the headband. It feels flimsy and not engineered well. The quality of the cans and driver is price appropriate. Also the coating on the head band is wearing off. But then my experience with Chinese headphone in this area is grim. I have used Hifiman and Ibasso headphones. And is dissappointed with quality of the mechanical build. The Harmonicdyne is the better of the lot.
To sum up, I dont think its worth the full price siince I got it for a good discount deal.