One of the last holdouts on the Unison upgrade.
Summary: If you have a MB A1, and you plan on keeping it for a few years, then do the upgrade, it's better in every way, and it extends the warranty 2 years.
It's not just better with USB, it's better on coax too. I liked it out of the box, and was wondering maybe I would not hear the 3-4 day break-in. But indeed it kept getting better, and stopped somewhere between 72-96 hours. I repeated it 3 times, and its a thing, has been since I had it.
Whats better?
clarity and focus on instruments mids->high. Initial fans like me were drawn in by the analog type sound, but, there was also smudginess/lack of clarity, which is now clear. But this new clarity is still pleasant and the harmonics are still full and intact. A really fine set-up not only draws your ears to the instruments and staging, but also the spaces in between, and there is quiet and emptiness where it should be. This is more than the OG did. I'm free to enjoy the music, what's better than that?
I can't find a downside. It's still great pairing with the Rag 1, which is a bit drier, and not romantic per se. It's the last piece I have that I would update.