In the end I've sold both to go with an NOS R2R DAC and sound, but both were excellent in my view.
After your time with the M3 which NOS R2R DAC are you considering?
Recently I came very close to pulling the trigger on the Bricasti MC1. I'd be upgrading my dated Metrum Acoustics Mini NOS. Without much experience I'm skeptical of losing the Metrum's basic presentation.