Those who know, know. Serious quality but I would recommend being careful with the handling, especially with the plugs that are necessarily right and left and you move them every time. A good cable cover and a stand. (Topping A90/d needed)
The earpads, although top in quality and sound insulation, I would expect them to be a little more comfortable (they are a bit flat).
The weight is good, but the cable is a pain.
Because you won't find earpads from Sennheiser for a while longer, be careful. Not on bare skin during summer with heat, etc. Until they release replacement earpads, I would recommend light use or a hat so it doesn't touch filthy skin and hair.
They don't work without an amplifier* Find a good 300ohm+ impedance with a full balanced 6.3mm jack