The HS sits relatively comfortably. I have no complaints (but say sometimes that I do not have oversized head ..).
The sound is for the 20 Euro fine. One should not expect any audiophile miracle. But to play it enough.
The microphone seems to fulfill its purpose. At least I have not heard any complaints. You can adjust the whole in height and closer to your mouth and away again. No reason to complain here.
Yes, the HS consists only of plastic. I have no idea how long it will last, but it use not daily.
Conclusion: For the price of just 20 euros one makes as Durchnitsgamer certainly nothing wrong. I just hope that I do not so quickly have a loose connection and keeps the HS good in itself.
Otherwise, I think I will retest the much-hyped combination of 'right' headphones and separate micro-next time.