@garebear, I cannot answer your question if you should purchase the Bricasti M21 DAC or the Berkeley Alpha Reference 3. The answer depends on your budget, audio goals, what you are trying to accomplish, your existing equipment, your listening room and many other complex factors. I have no listening experience with the Berkeley Alpha Reference 3.
My Bricasti M21 DAC (MDx board installed) is outstanding, and I highly recommend it IF you have the budget, supporting high quality equipment and you want state fof the art sound quality. The addition of the M21 substantially improved the sound quality of my audio system. To my ears, everything sounds truly outstanding. The music is clearer, less dark, better bass and sounds more like music.
Bricasti says "The M21’s “advanced architecture means you can select, evaluate and enjoy three independent digital to analog converter signal paths: 24-bit delta sigma, 20-bit ladder DAC and true 1-bit DSD for DSD content. Engineering autonomous conversion paths creates an efficient platform for you to enjoy your music and explore the advantages of each”.
I experimented back and forth between the delta-sigma DAC and the ladder R2R DAC. Two weeks later, I set the DAC to the ladder R2R setting and rarely move it. To my ears, the music sounds better.
The M21 is a world class DAC and is highly recommended. I have no experience with the Berkeley Alpha Reference 3.
As was posted above, I agree that Bricasti customer service is excellent. Bricasti is a top-notch company. Bricasti supports its products and offered the MDx board upgrade. I installed the Bricasti MDx digital in my M21 DAC and the sound quality substantially improved. The MDx board is an outstanding upgrade and is included with all current Bricasti models.