I received the Empryean as part of the Headphones.com Meze Empyrean Tour and I can’t thank enough @TylersEclectic, @taronlissimore, and Headphones.com for setting this up!
I’m new to the hobby and this is my first time sharing my thoughts about headphones, so bear with me 
I currently own the Sennheiser HD6XX and the HIFIMAN Sundara. Empyrean is the first TOTL headphones I had the chance to listen for long hours, which means that I won’t be able to compare it to other TOTL headphones.
My chain was Tidal → Roon → Raspberry Pi 4B running RoPieee → Schiit Modius → Schiit Asgard 3. I used oratory1990’s settings for EQ with two minor changes (low shelf at 105Hz to +6dB and high shelf at 10000Hz to -6dB).
First of all, the build quality is fantastic. Empyrean comes in a black aluminum suitcase. After unboxing, I found myself appreciating the details of the design. The design is definitely not minimal, but the elements are blended together beautifully. I would also strongly recommend checking Meze’s website to learn about the engineering story behind the Empyrean.
The Empryean comes with two sets of pads (Alcantara and leather). I found the Alcantara pads more comfortable so I used them for the most of my listening. Alcantara pads also seem to have a slight warmer sound but I didn’t spend enough time to compare the pads to be honest. The pads are magnetically attached to the cups which makes changing them a breeze.
The Empyrean comes in at 430g but it felt much lighter and much more comfortable compared to my Sundara, which comes in at 372g. I usually need to adjust my Sundara a couple of times during listening, but with the Empyrean, they are so comfortable that I didn’t need to touch them again after the initial adjustment.
In terms of how it sounds, instrument separation was the thing that impressed me the most. I had a lot of “I didn’t know there was X in that part of this song” moments. And it’s not like the headphones were trying to drag your focus to a single instrument. For example in Opeth’s Ghost of Perdition, you can hear every single instrument individually but also all of them at the same time in harmony.
I’m probably guilty of liking the bass more than I need to in general to but still, I enjoyed the bass on the Empyrean. I wouldn’t tell that it has the slam, “tightly controlled and fuller” are the best words I can think of to describe it.
I found the highs enjoyably bright. I’m usually easily fatigued by piercing highs but the Empyrean was just right below that for me. For example, the cymbals in the intro of Gojira’s Stranded were so good that I listened to the intro only for maybe 10 times.
Mids were probably my least favorite part. They were still good, but vocals, especially female vocals like Joan Osborne’s One of Us or Draconian’s Pale Tortured Blue sort of sounded distant to me.
While I thoroughly enjoyed the Empyrean when listening to well-mixed songs, they were unforgiving of anything that didn’t have at least decent production quality. This was especially apparent on metal albums. I think this is where my HD6XX shines
Overall, I think the build quality and comfort of the Empyrean impressed me more than its sonic performance but again, I don’t have the listening experience to make an apples to apples comparison.