Cons: Ineffective 3D wing support system means they're not suitable even for home use
I owned the original A900 for many years, it was a fantastic headphone. After it was stolen I ordered the A900X from AudioCubes in Japan, slightly nervous because I'd read of problems with the new 3D wing system.
I was dismayed when the A900X headphones arrived that the widely reported problems with the wing system were true. The only thing holding them to my head (slightly smaller than average) was the low to moderate clamping force, the 3D wing provided no support at all. Sitting entirely still they stayed in place, but as soon as I moved at all in my seat they slid down. Before long they ended up resting on my ears, which is uncomfortable. Putting a rubber band between the two wings mitigated the problem, but was too ugly IMHO, and you shouldn't need to fix brand new $200 headphones. They were returned to AudioCubes who sent them to Audio Technica for repair, but I was told they worked as designed.
I never even listened to the headphones, as if they don't sit on your head properly there's no point. I'm sure they sound fantastic, like the original A900.
I recommend against these headphones on the basis of poor design and support.