Have you heard darTZeel Amplifiers

I’ve been interested in a darTZeel NHB-108 amplifier since hearing about them a few days ago. Has anyone heard a darTZeel amplifiers and what is your impression? I was intrigued because their NHB-468 has a very high slew rate of 200v/µs, which is the highest I’ve ever seen. The NHB-108 model 2 is rated at 88v/µs. I have always been impressed with amps that have a high slew rate because they sound transparent to me and reproduce transients other amps seem to miss. I have had many amplifiers including a modified Sony TA-8650 which has a high slew rate, that will go in my estate if it lives that long. I like the sound of Bryston amplifiers a lot too. I realize the price is high for darTZeel even used, but I’m looking for something because I would like more clarity in the midrange especially. I don’t want to even consider tubes unless they have an auto-bias feature. Thanks in advance.