Just wanted to share some thoughts after few weeks with XM3.
First I think the bass is really elevated. Second I really think it is fixable with EQ, specially if You are within AAC like I am. I did an EQ:
https://files.fm/u/5s94a5fu
and even today did a A/B with XBA-Z5 and well they are far from the same fidelity, but they are really not in a different universe here, playing TIDAL HIFI->DragonFly RED->XBA-Z5 vs IphoneX, TIDAL-> AAC->EQed MDR-1000XM3. Also, one important thing to me is that from what I checked the EQ is kept valid through my IphoneX or Ipad Pro unchanged so if You set it up for BT it should work on all devices that let EQ to be applied. Obviously I would love them to have more bite in mids, I would love the bass to be sharper a bit, I would love the highs to wisper more but, for NC these are amazing and I really love them. After, Bose, H9, H9i, PX ( love here ) , these are by far the best NC BT headphones I tried.