MLGrado
500+ Head-Fier
First, LCD X and Ether Flow are two different sounding headphones to me. Audeze line will always has this warm, seductive and addictive quality with bass slam which no other headphone in its class able to reproduce. While Ether Flow seem to focus on detail retrievals and clarity. They both have sound stage and air but being presented in their own ways. As far as I remember, the Flow seem to have more air, cleaner and more vibrant with bass response that is better than it's little "sister" Ether but still not to the level of slam and weight that LCD X has. LCD X still has this fuller and weightier and more body to the sound. Both are really excellent it's just a matter of taste at this point.
A strong reason why you should get Flow instead on X is the weight differences.
When I had a pair of LCD-2 Fazor from late 2015 my reservations about them were the too dark and distant (for me) treble and the weight after long listening sessions.
Now with the LCD-X the only reservation I have is the weight.
I have read that you get used to it after time. For me, the worst part of it is fatigue in my lower rear neck muscles and upper shoulders.
I wish I could brush it off as a small issue for me. If it were not for this crazy good sound I don't think i would be keeping these. But the sound is WORTH getting used to the weight.
I want to hear the Ether flow, though. I do value air and vibrancy. The LCD-X has enough, actually it sound quite well balanced overall. But sometimes I like the fun factor of a really vibrant, texture filled 'airy' listening experience. Must be the audiophile in me...