I wanted a USB device with bitperfect ASIO support that could do format conversions to AES. This box absolutely does that. The software is very good, no glitches. It appears to Windows like every other ASIO device I have and it is recognized by all the apps I'm using.
There are a few things I would change about this but none of them are major deals for me.
1. It seems more likely S/PDIF would benefit from reclocking than AES, so I would have preferred if there were two AES XLR outputs rather than one each of input and output. But as it is there's pretty good connectivity here. The back panel is impressive. Just about everything is there.
2. The UI is really nice and dead simple. The menu operation is so well thought-out you almost don't need the manual- which I think is an excellent manual. But I'd like to see some indication of input bit depth, either three LEDs one each for 16/24/32 or one LED that changes color. Some output devices need bit depth set and if you don't know what it is it can be annoying. Bit depth indication would save some time.
3. The device can handle DSD256 over USB. Annoyingly, there is no BNC output for DSD, everything is converted to PCM. I think it would be worth trading one pair of wordclock output jacks for true DSD out over BNC.
The unit feels solid and although the power switch is annoyingly on the back panel, it is extremely positive. It snaps hard on or off and will not bounce. Really nice hardware. Heavy cables so far do not push the unit around.
I don't have any comments on the sound quality yet because that wasn't the main reason I bought it.
Update: the plastic door on the optical S/PDIF output broke off inside the housing the first time I used it. Although it took some time to receive a reply, Mutec stood behind the product and offered to repair/replace it or send me another optical socket. Thomann is also looking into the case. So I'm disappointed about the quality of that socket while the rest of the box has been great, and I'm happy with the concern and support of Mutec and Thomann.