Not bad, really bad !!

A very good sound, but not neutral super good! It connects easily bluetooth, like many charging and active noise reduction is correct with a smartphone or other use.
However the only negative aside its price, it is also this noise reduction !! What horror to listen to loud music volume on a DAC with music in FLAC ... As mentioned in the lesnumerique test, it's pretty yucky (the helmet loses neutrality brings out more bass with poor quality) but when you plug the wired headset with the power off, the active noise reduction does not turn, and it's a treat.
Last regrettable point is the cable that came with it is thin, it is short, and no one has the impression of having a cable to Sennheiser quality, it's a shame, because the accessories (wallets + case) are good bills.
A longer cable, better quality would not have been a luxury.

I recommend it, or maybe wait a little price drop to buy it (this have to happen)