I just purchased a GS-X Mini but it hasn't arrived yet, maybe early next week it will be here.
DAC-wise, I am currently using the AK SP1000 as "DAC". However, will be testing out a JDS Labs Element II as DAC soon as well.
To upgrade, I am looking at the following:
- RME ADI-2 FS DAC
- Chord Qutest
- Mytek Liberty (Same DAC as the original Brooklyn)
- Mytek Brooklyn DAC+ or Bridge
Don't have the means right now unfortunately
However, I do have a friend that has both the RME and the Qutest with the GS-X Mini, and he prefers the RME. He says its smoother and more musical compared to the more clinical Qutest.