I had an original A1 (USB 3) and later an A2 (USB 5). Both sounded really, really good from coaxial inputs. On each new USB version they kept claiming it was finally "there" with traditional coax, but let me tell you - USB 3 and 5 both really sucked, so color me skeptical about the Unison (I know it’s been out a while now).
Both OG Yggys sounded much better than an OG Gumby - I don’t get anyone who claims to like that one better. It wasn’t close.
Both my OG Yggys developed issues that required repair from Schiit. One had a control board failure (no input / bitrate switching), the other a choke failed (no signal from outputs). It’s very rare I’ve had any electronic components with problems (other than very high voltage electrostatic headphone amps, which is a different animal), and I’ve had a LOT, so being 0 for 2 here really sucked.
I ended up with DACs I like better than Yggy OG (Phison PD2, Meridian UltraDAC), though at much greater expense. I think the OG does deliver on its promise of sound quality beyond its price point. I’ve read enough to concern me about the SQ of new LIM / etc models, I’ll just avoid them if I get an itch to own a Yggy again (not likely because of their failure history with me).