I have had them for a few days, but I decided to write a review.

Sound quality:
I will start with the most important aspect. It is amazing in every sense of the word. Detailed, crystal clear, flat sound. To put it differently: it's like having miniaturized Zensor speakers in your ears. Also, what we read in reviews about hearing sounds we have never heard before, etc., that's exactly what happened. I also have the Sennheiser PXC 550. The Dali headphones surpass them in terms of sound quality, no question about it. I mention this for comparison purposes that may help someone.

Comfort - Build quality:
The quality of the materials will be judged much later, but the initial impression is excellent. Even someone unfamiliar with them will realize that they are a premium product. They are quite comfortable (not perfect), they fit the ears without any problem, and the earpads are very comfortable. Additionally, the hinges (specifically the plastic that supports the earpads) rotate 180 degrees and provide the ability to tilt, which allows for a better fit around the ears. Some may find the headband a bit uncomfortable; you feel a slight pressure, but it's not a big deal for me. However, the PXC 550 headphones excel in this area.

Isolation, volume:
Very good passive isolation. In the few days that I have had them and have traveled on the metro, I have not regretted spending the hundred euros on the io6. The volume on the headphones is quite good. Keep in mind the relevant regulations of the EU so as not to damage your hearing.

Buttons - Controls:
They do not have touch controls, but buttons that function in the familiar way for play/pause/forward, etc. The controls respond well and quickly. Holding down the button for an extended period opens Google Assistant (presumably Siri as well if you have an iPhone).

Connection - Call quality:
Bluetooth 5.0 with aptX HD, aptX, and AAC. Very fast and stable connection without any issues. Call quality from my end is excellent, no complaints about external noise from the callers. Analog connection is also provided, along with the corresponding inexpensive cable, which is quite convenient.

Battery life: 60 (!!!) hours with USB-C charging. I don't need to say more about this.

Negatives so far:
Relatively large in size.
No hard case provided, like the io6, only a pouch. Dali sells it separately for 40 euros (ridiculous) on their website.
The analog cable does not have a microphone. Another flaw from the Danes.