As most don't have fit issues, they are a really fantastic headphone.
With most of my listening through my electrostat loud speaker, and how the HEDD gave me a terrifying hotspot, I had to give them up.
You've given up the HEDDphones? It was only a few weeks ago you were saying they were the only phones you needed, that they bested the Stax 009/T2 combo you used to have.
I'm curious about the hotspot - you mean your scalp heats up under the band? I haven't had that problem but they sure do heat up my ears, and after only half an hour (to be fair, other hard-clamping phones are just as bad).
But ergonomics aren't the only problem. I have the 009s and a couple of really good DIY tube amps (not saying they are as good as the T2, which I've never heard, but certainly in the same league as the Blue Hawaii etc.) and in a direct comparison the HEDDs don't come off well, listening through my 3 watt DIY hybrid amp in balanced mode and using very low capacitance custom cotton hp cables. The 009s run circles around the HEDD in detail retrieval, transient response, subtle timbral discrimination, and soundstage depth and transparency, and are at least their equal in dynamics (though maybe not slam). The 009s too have a bump in the 1-3K range but the effect is different - the Stax sound "sunny" (not bright exactly but not quite natural either); the HEDD sound bright and hard, pushing the sound out - the opposite of relaxed.
But ok, the HEDD cost only a small fraction of the 009s + a really good amp. However, I've been listening again to my LCD-3Fs, which I've had for several years but hadn't put in a lot of time on because I preferred the 009s and even my Lambda Signatures. Anyway, I've been really surprised at how good they sound. They used to sound dark - better than the LCD-2s but still with not enough energy in the highs to make cymbals ring convincingly, for example. But no more. I can't explain this change of perception. In any case, compared to the HEDDs, and on acoustic or mostly acoustic music (jazz, classical) they just sound more like the real thing.
If you really want to test the abilities of a transducer you have to feed it complex material about which you have a pretty good idea how it should sound. For me that's orchestral music. Starting with the string section: the Audeze have more texture (definition) and especially better mid-to-low bass (double basses sound nice and plump but still articulate). Woodwinds are sweeter, the brass have more body, and low percussion (bass drum and tympani) that sounds a bit shallow on the HEDD seems all there timbrally and dynamically, even though the 3Fs are rolled off in the sub-bass. Another thing: the 3Fs retrieve quite a lot more low-level ambient detail - the resonating space the music is bringing to life is more palpable; the HEDDs sound drier, closed-in. The 3Fs are surely somewhat euphonically warm, but even so they make it easy to forget their sound and just listen to the music, whereas for me the more constrained, less timbrally realistic sound of the HEDDs has become hard to ignore.
Another difference is soundstaging: the 3Fs have more depth and I think width as well. There's something paradoxical about the HEDDs' soundstaging: although they often sound upfront with less complex music, orchestral music sounds somehow pushed back and miniaturized - out of reach. Certainly they don't layer as well, but it also comes back to a relative lack of detail - first violins sound like a unified section rather than 25 or so violins playing (almost) together. With the Audeze I feel more engaged in the space in which the music is happening, it feels like I'm physically closer to the music-making. The HEDDs/ presentation is more compact and forceful. That might be a plus for genres I don't listen to.
Obviously this is a minority report - it's almost as though I'm listening to a different headphone than most other people here. When I first heard a demo of the HEDDs I was impressed and decided to buy a pair, but after a while, listening to them at home and comparing them with my other phones, disillusion set in. I have heard and liked AMT speakers, and I'm still interested in hearing what HEDD can do with a concerted TOTL phone. But maybe the fact that the HEDDs went through 25 iterations before being finalized is an indicator of difficult technical issues in designing AMT drivers for full range.