GOOD DAC / Amp is required to get the most from Audeze's. I don't really see the Gustard as a good option for a headphone of this caliber. I drive my Audeze LCD3's with a $5K system. Gustard, no.
hanzySide by side, to my ear the H10 sounds better. But it's all subjective... You are right though. This is one amazing amp. It has impressed a lot of people with way more knowledge than myself time and time again.
Lostdog54M2Tech EVO USB/SPDIF converter with external clock, Headroom balanced DAC, AMP and Desktop power supply, LCD-3's. Sounds amazing and still cheaper that setting up a hi-end home system.
If I were to by again, I would opt for the X.