I have been testing the USB input of the Mimby, USB to Coaxial part of the Fiio E10, and of course the Schiit Eitr just to see how the Eitr and the A2 firmware have been working, Here are some quick notes
Mimby USB: Has a congested and energetic presentation of the music compared to the E10/Eitr. Feels bloomy at times (especially drums) Thankfully this is still less energetic than A1 firmware
E10: The soundstage feels more open now, details are easier to pick out and therefore give an impression of less energy when it isn't the case; it's just you being able to hear the other details better and thus focusing more on that
Eitr: Soundstage opened up a bit more and details are even easier to pick out, especially since higher frequency stuff like cymbals and organs have a special "air" that simply cannot be heard in the E10 or direct USB to Mimby
tl;dr so far: Eitr > E10 >>> Mimby USB
@julianlopez85 you may want to stick with your plan to get a decent device that can do USB to Coaxial converter. Some DACs out there still do USB to Coaxial so this can be a substitute for Eitr until they come back to Clearance section or when you move up to Biifrost 2 onwards (their Unison USB should have resolved the harshness I think)