Had a great time, and was pleasantly surprised by the gear available to try! A few quick impressions while they're still fresh in my mind. Mainly of headphones, since sources IMO are the hardest to evaluate in meet/demo conditions with all of the noise around.
ZMF Atrium Closed: probably my current favorite of the ZMF offerings. Unfortunately, I missed out on trying the Verite Closed as I had wanted to get updated impressions since I wasn't very impressed with it last time. But between the Atrium Closed and the Eikon, the Atrium was noticeably better to me, more open and airier compared to the Eikon. Couldn't really choose between the soft wood and hard wood versions, the hard wood seemed to have sharper attack on transients compared to the softer and warmer sound of the other.
Arya Organic: Less "scratchy" and harsh than the Arya Stealth. I've seen the measurements that show they have an enormous amount of treble, but I don't think that the treble is too much or too harsh. It's probably the increased bass that counteracts the brightness so that the treble manifests as air and sparkle which I like.
HE1000se: Brightest of the egg-shaped Hifimans that I've heard. A little too zingy for me, and I think the Arya Organic or (from memory) the HEKv2 had calmer treble.
HD800s: Noticeably wider soundstage than other headphones, but somewhat tinny sounding and otherwise not particularly impressive. Bass was also mushier than on my SGL Jr even when both were on the Erco (though the Jr was driven also by the modded SRM-006tS). Still not quite as open-sounding as the high-end Hifimans despite the wider soundstage. Missed out on the HD8xx as I didn't have a DAC connection available.
Voce on the SGL Jr Amp with iFi portable DAC: Bassy, but also kind of mushy bass, veiled midrange and vocals, lacking in air and openness. Not particularly pleasing or impressive. Probably needs a more powerful amp (Dan Clark uses the BHSE for development in house), but did not have the chance to try it on the BHSE, alas. May also benefit from a more dynamic DAC, as my friend tried the Voce out later on my Erco+Shunyata combo and liked it.
Jade 2 on the SGL Jr Amp: overall pretty similar sound to my SGL Jr, but with less subbass and less bass impact. Not as much clarity in midrange and treble, but also less risk of being too sharp with an aggressive chain.
BHSE: wonderful amp, but without a familiar DAC, comparisons are difficult. Seems to produce wider/deeper soundstaging on my SR-L700mk2 compared to the amps in my stable. Bass sound more solid as well. Well-worth another demo in quieter conditions, but also difficult to find room for it in my current living arrangement. Edit to add: the headphone sockets are extremely tight on the BHSE. Inserting and removing headphones required that I hold the amp tightly otherwise it would slide around. Maybe different feet would help (it was flat metal feet on a slick plastic table).
Audeze CRBN: similar impressions as the last time I heard it, despite using a BHSE now vs a modded SRM-006tA last time. Good bass (better than Voce for bassy estat, though I haven't heard the SR-007), relatively forward mids (in line with the new Audeze house sound), generally lower treble which reduces the air and openness of the sound. Good headphone for those wanting a bassier estat, but I didn't find it particularly compelling.
Aurorus Audio Australis: Possibly the most distinctly punchy headphone that I've ever heard. The dynamic punch in the leading edge of drums is unlike anything else I've heard to this point. There's this sharpness plus a bit of reverb at the peak of each note which I don't recall hearing on any other headphone. It's very engaging. It's also very bassy in addition to that punch. Vocals are distant and slightly veiled, treble is noticeably rolled off. It's a distinctive sound, and one that I could definitely see as a part of a collection.
HarmonicDyne [something-or-other, couldn't see the name, it was the purple headphone on the left]: The exact opposite of the Australis, this nameless headphone is totally nondescript. No major tonal flaws, nothing particularly strange about its presentation, a bit softer impact on bass than I'm used to from planars and estats, but also entirely without exceptional merits. It sounds "fine", where "fine" is a synonym for "mediocre". Honestly can't even remember what it sounds like other than the softer bass impact.
Modhouse Audio Tungsten Double-Sided driven from a big Schiit amp (Jotunheim? Mjolnir?): a much-anticipated headphone in the community, but no longer anticipated by me. First, it's pretty heavy; noticeably heavy on the head and the earcups are awkwardly large. Sound-wise, it's a very intimate presentation with vocals noticeably forward and close to the face. Only comparing from memory, but it sounds even closer than on a HD6xx. This sort of kills my interest in the headphone unfortunately, since ultra-forward vocals are a major turn-off to me. I want my vocalists to "step away from my face" as it were, to have the illusion of distance from me. This goes the exact opposite way. Other than that forward presentation, it's a rich and "weighty" sound with lots of force behind bass notes and such. I just prefer a different presentation of bass that "retreats" quicker after the initial impact.
I know a lot of these impressions sound like harsh criticism, but I don't think I heard a single bad headphone during this meet. IMO it's quite difficult to make a bad headphone if the designer puts effort into designing it. Most headphones sound fine, some sound good, some sound special, and a few sound good and special in ways that intersect with my preferences. The headphones that I disliked were the ones that really leaned into an aspect of sound that I just happen to not like, and I'm confident that someone else will love them.
