Warm sources will pair up better with a lot more than neutral/dry ones which will make brighter headphones, and/or neutral ones sound a little lifeless. I prefer having a small margin of error where everything will still sound a little more musical.
The Compass 2 with ES9018 just made certain headphones sound...lacking.
Had the NFB5, as well as SA-31. Both were more suited for me and made headphones sound better than the Sabre equipped Compass 2, IMHO.