Which would you pick between the two DAC.

Dave,

Thank you.  I will take a look at it.  I almost get ISO Regen while back when I first got Modi Multibit and had noise problem with USB signal with iMac.  What I did was I disconnected usb 5V from iMac and run 5V from the wall and no more noise.   

Thank you everyone for your input.  

Exogal Comet Plus is awesome. I believe they are the Wadia engineers from before the recent corporate takeover. 

Agree that the Comet Plus is a special and very good sounding DAC. A true bargain at street price or maybe at any price. Its resolution raises my bar yet brings the slightest imperfection/mismatch of accompanying cables, cords, fuses, etc into the forefront. Purist Audio's top products proved to be the answer in my system, room, ears.

The executives of Exogal and the Chief Engineer Jim Kinne were indeed the brains behind Wadia in its glory days.

Dave

If you dont have to have DSD there is  a new Wadia 321 on Ebay for ~$1.2, which in my opinion is a good deal as it was originally $3K.  I have the same model and the only real difference between this model and the di 321 is the DSD capability but you might want to verify that.  I have the regular 321 and I bought it to match up with a Rogue RP-1 and a class D amp.  My 321 gets played daily and when I work from home it's cranking all day and has not missed a beat. There are a few detail reviews out there on the regular 321  but have not searched on the new di.  I really like my 321 it surely helped take the edge off and extend the sweet spot for my class D amp.  Also Wadia, for better or worse, is now part of the Mcintosh Group.