I also got a chance to hear these recently at CAF this weekend, I will say out of an LTA MZ3 with my HM901 I wasn't super thrilled about the mid range as it lacked the warmth that I appreciate about my own original AFC.
An for reference my ideal mid range is that of the ole school AKG K501 and more recently what I hear from the Koss ESP 95X at home for more tru high fidelity listening the HD 800 with SDR Mod and an Audio Envy ToneKraft Copper Cable out of a heavily modded SET Tube [RME ADI 2 with Sharp Filter as Source] is also quite nice as is my own 2012 PreFazor LCD 2.2 with a ZMF 2K Copper cable
So my mid range preference aside what I will say is they were quite spacious and precise, hearing
@MattTCG thoughts of this as a purely Hi Fi headphone is on point. I felt staging wise these were a bit better than the ZMF Veritie Closed that was also present, tonality on Verite Closed was great but the presentation was too disjointed for my tastes out of the systems present
Back to A2C, I didn't like it on my portable rig but that's been optimized for OG AFC. For what it's worth I also I don't run my HD 800 out of that rig as the tonality is not quite right for headphones of that nature. So my qualm with the midrange is likely my choice of amplification, thankfully I also have an OG ALO RX MK3B that has just the right touch of warmth. I have a feeling that amp would get A2C exactly where I'd want it tonally without much loss in that beautiful staging/imaging and it'll all still be portable!
I'd also like to comment on the consistency of ePads on A2C! As some one who has struggled to get a pair of matched proper ePads on OG AFC I was immediately impressed by what A2C had, same style I think but the pads felt a touch denser and not as flexible. The issue I have on OG AFC is one pad is larger/more flexible than the other and yes this was after having a replacement pair installed by what was Mr.Speakers. An for AFC I really feel it's presentation is so fit dependent.
Non the less I'm digging the new name change as I always wondered why it was Mr.Speakers after they began making so many headphones and I'm excited to hopefully get to hear these again with a better portable set up or from something in home that's more my speed.