I picked up a used pair of the U6t and they arrived a couple days ago, so these are my impressions after about 6-8 hours of listening to them (so take my opinions with a grain of salt).

As background, I am more of a headphone guy and this is only my third pair of IEMs (so take my opinions with a grain of salt).

I listened to them using either my iPhone with the apple dongle or with the FiiO Q5S. They are powered well off of the apple dongle and I didn't notice a difference. All of my listening has been with the m15 apex module.

These are fantastic IEMs for enjoying music. They provide an engaging and dynamic presentation, have a fantastic tonal balance, and come in a sleek and comfortable package. Their detail is not on the level of headphones like the Verite Closed or LCD-XC (I don’t have much IEM comparative experience), but to be frank it was good enough that I didn’t care one lick.

The soundstage was minimal, maybe slightly better than other IEMs I've heard. The instrument separation was quite good.

I didn't think that I'd like the aesthetic of the U6t (looks a little industrial), but I have to say that they are really sleek and more understated than I thought they would be.

The comfort on these is fantastic. The U6t only really touches my ears at the tips which sounds a little crazy, but ends up being incredibly comfortable. I will say that I tried jump-roping with these in and that wasn't a great experience.

The accessories are a solid set including a bunch of tips (6 pairs), a really nice cable (for a stock cable), a cleaning tool, a nice case, and the apex modules.

My crazy take: in my very limited experience I would say that the 64 Audio U6t is almost ZMF-like, as if the Eikon and Auteur had a baby and that baby was an IEM. The U6t hits hard, has fantastic timbre, and has an engaging and fun frequency response, though the bass doesn't rumble in the same way. That’s how I felt when I heard the the Auteur and Eikon and fell in love with ZMF and that’s how I feel right now with the U6t.

Comparisons:

Moondrop Blessing 2 (not dusk) - I really liked the Blessing 2 and it has some similarities to the U6t, especially in their strengths. More specifically, I think both IEMs excel in both excellent dynamics and timbre. The U6t is better in both, but if I was to compare the new price tags I would be disappointed in the only modest improvement. The frequency response is significantly more to my liking on the U6t. The bass and mids have better separation on the U6t and though both IEMs have a lot of treble energy, the U6t never feels bright to my ears. The U6t is smaller, sleeker, and way more comfortable than the Blessing 2 for my ears.

Thieaudio Oracle - I wanted to like the Oracle so badly (mostly because I love the aesthetic), but sadly, I found that the Oracle did not agree with me. Where the U6t is engaging and dynamic, I found the Oracle to be clinical and dead. Yes the Oracle was pretty detailed and sounded quite clean, but I rarely found myself lost in the music. The limpness of the impact on the Oracle as compared to the U6t (and Blessing 2) is a bad memory for me. Also the difference in treble is night and day and heavily leans to my preferences for the U6t. The U6t is smaller and way more comfortable than the Oracles for my ears, but I do love the look of the Oracle.

Overall I am really impressed the U6t and although I’ve only been listening for a short time, the honeymoon period (so far) has been memorable one. Only downside is that I’m now really intrigued to hear the U12t.