got my aeon's this saturday afternoon and have logged about 8 hours so far with them, so i'll give some very early impressions, and comparisons to my beyer t5p2 (my current closed favorite).
the easy stuff first, it's well built, fits nice, is very comfortable, and looks much better in person than in pictures, imo. i have a standard 4pin xlr, and the stock dummer cable with 6.3mm termination. i'm listening via xlr on my jotunheim/modi multibit combo.
my early impressions are quite positive. the aeon sounds clean, precise, and well balanced. there seems to be a slight upper mid emphasis, but it could just be my aging ears. coming from the mad dog pro and alpha prime, i'm especially impressed with the treble. the older mrspeakers always sounded a bit ragged in the upper regions. the aeon, on the other hand, sounds quite nice in the treble region. micro detail is very good. i especially like the 6-9kh region, its sparkly, well defined, yet smooth. no raggedness here thankfully. the prime, in comparison, is much less refined sounding. calling on the prime again, i find the prime to be warmer overall, with a more emphasized bass attack. the aeon is much more linear in it's bass presentation. when bass is called for, the aeon hits hard, and digs low, with very good slam. but it doesnt interject bass when not called for, like the prime would (just a bit). overall i much prefer the aeon to the prime, it's a more refined and accomplished set, to these ears. these have minimal hours on them so we'll see if burn in changes anything, though i'm kinda doubting it. i notice no difference from hour 1 to hour 8 so far. my ears are abused though...
ok my current closed fav, the t5p2. i wont go into a lot of detail as i've yet to really put good effort into a thorough comparison (i'll do that after i've logged a month or more on the aeon's, and know it better). but as of right now i would not say the aeon dethrones the t5p2, imo. why? i find the beyer a bit more engaging to listen to. it's not as neutral, but i think that's a good thing. it's bass is a bit warmer, with more bloom (and BOOM). I like the rumble the beyer gives me, even if it's not exactly "accurate". i find the aeon's bass to be a bit polite in comparison. and for more linear. i know i am contradicting myself here as i said i disliked the prime for doing such, but it did it in a way that just didnt sound as good, and i am honestly unable to explain exactly why. i just didnt like the prime's bass warmth nearly as much as the beyer's. the mids of both sets are very good, with heaps of detail, though the beyer's are a touch more forward. this adds a bit of excitement that the aeon lacks. and though many dislike the beyer treble, i personally find it very engaging. i disliked the first gen t5p treble, it was too bright, but the gen 2 was pulled back just enough to approach "bright", without going over top, like the first gen would. the aeon treble is a touch smoother, with less attack. but overall, i find the treble to be the most similar between the two cans.
overall the differences between the beyer and aeon are slight, but enough that so far i'm still preferring it. and the one area i find the beyer completely walks away from the aeon is in soundstage. i am always surprised by how good the beyer soundstage is. and i dont have to qualify that with "for a closed can". to my ears, it's wider and deeper than my hd650 and sr225e, both open cans.
please dont think i dont like the aeon, i like it quite a bit. i feel it complements my t5p2 quite well for a work can. i prefer the beyer for my more poorly recorded rock/metal tracks, it seems more forgiving, and is more exciting. for my higher quality recordings, like jazz/classical/vocals, i prefer the aeon. kinda like how i grab my grado for rock and hd650 for jazz/acoustic sets.
one final thing, the aeon requires decent amplification to reach it's potential. the jot has more than enough power in either se or balanced configuration. on my fulla 2, things get a bit more challenging. the fulla 2 can get them to deafening volume easily, but i find dynamics suffer a bit. bass slam isnt as hard or tight. there's more bloom, with a slower decay. the highs get a touch brittle too, i find. it's not horrible, mind you, but coming from the jot, it's definitely noticeable. i think i'll grab a vali 2 for work for the aeon. the t5p2 is easily powered by the fulla 2, as it's much more efficient. i also tried the aeon through my dragonfly red, and again, i found it lacking in power. volume was fine, though i had it up to about 85% on my iphone 7. but again, dynamics were lacking. it just sounded dull and lifeless compared to the jot. if you're thinking of using the aeon as a portable headphone, i'd strongly suggest a strong portable amp like the mojo, or equivalent.
i'll let my ears/brain adjust to the aeon, and let them burn in for a month, and revisit my impressions then. but overall i'm really impressed with them. i think they're a clear improvement over the alpha prime and earlier mrspeakers. i have the non-flow ether, and i'd say they're on similar levels, just different flavors. the ether is even more neutral and resolving, but not as engaging. i've yet to directly swap back and forth like i did the beyer, so i'll add those impressions later.