Gryphon has a fair amount of noise (Balanced Out) which can be eliminated using the inbuilt IEMatch setting, toggling it "On" does increase the Output Impedence upto 10 Ohm if I remeber correctly, which effects the frequency response of some IEMs for better or for worse.
It's been a while since I sold my xCAN but I don't remeber it being noisy. The XD-05 Plus has some noise (less than Gryphon), XD-05 BAL has even lesser noise. You can get the IEMatch accessory if you do notice noise with sensitive IEM's.
As an AIO package, Gryphon does a lot of things right, but if you don't need the extra features i.e. purely considering sound quality, it's not worth the cost. To my ears, the micro iDSD Signature was a better product for a modest increase in price over the Gryphon. the XD-05 BAL is a better AIO option IMO because it costs less and sounds just as good as Gryphon with the ability to swap Opamps to tune the overall sound.
To pair with the RU6 and with cost to performence in mind, the xCAN>BAL>Gryphon.