Just Google-resurrected this 6-week old thread.
I too listened to the M-DAC this week and agree strongly with one poster above - I found it grey, grainy, flat and sadly unmusical - an audiophile DAC for computer geeks. Equally irritating was its smartarse display which I couldn't get to switch off, and the rotary knob which doesn't feel like a volume control. Technically brilliant it may be, but you wonder what kind of systems pink fish readers own - and indeed most reviewers. 4/10
The Rega DAC is far better but has a tendency to sound glarey to me. Maybe I tried an early sample. 7/10
The Arcam rDAC, in its natural form, is very good but limited in terms of bass and soundstage. With a £35 Maplins switch-mode multi-adapter power supply, however, it's absolutely excellent. I fear there are a lot of people 'upgrading' from rDACs who haven't tried this. 8/10
Haven't tried the MF.