Any opinions on the AMR Digital Processor 777 Dac?

Cmalak,
Yes I still have it at my office and using a Mac mini driving it direct to power amp (GamuT D200). Does not have any other source connected so couldn't comment on how good it functions as a preamp. It replaced a Weiss DAC202 in the same system.

It is one of the best DAC I've tried to date. At first it was almost a little soft and perhaps a bit too glowy, but after a month everything snaps up very well.

Having a direct USB implementation inside the DAC is superior (in theory) to an external box like the Stello U3. Converted USB can go direct to chip set as i2s without having the need to get converted from SPDIF again. SPDIF as you know is jitter-prone. XMOS chip set is the industry standard for asynchronous transfer and now used in most of today's asynchronous USB dacs/converters.

Kschiu,
My two cents here re 16-bit NOS mode.
The AMR 777 is excellent with high rez, but I wouldn't say it is that much better than competitors. The mode that sets it apart is the 16-bit NOS mode. I had several NOS DACs before, all of them would give you that liquid mid range and palpable timbre. The instruments just sound more real. However there are not enough air and usual the size of the soundstage would be relatively narrow. The AMR's NOS mode just retain those NOS qualities with lots more openness and "air". I think this quality is very unique in the market. If you listen much to 16/44 and like NOS sound, then this is the perfect DAC.