Ayre Acoustics MXR-Twenty and KX-5 Twenty owners...

I own the Codex and have bought the upgraded QB-9 Twenty. 
It is a definite upgrade.
I think the QX-8 is the only other model that comes close to the QB-9
I have no experience with the Chord, as I find Ayre components to work so well. I did use a number of Schiit DAC's, but the Ayre really smoked them.
B

Thanks for the feedback. I have been told by Ayre folks that Ayre products really work exceptional together. On the other hand I have heard comments regarding the Hugo TT 2 and many feel it outperforms the Ayre QX-5 Twenty, even with existing Ayre gear. 

If your decision is close, I would personally opt for the Ayre based on synergy with your gear, and Ayre Acoustics' unsurpassed service and support.   

I suggest you consider the Meitner MA3 streaming DAC.  I use one into a KX-5 Twenty.