i just signed up to reply to this, i have kinda similar experience with you!I am completely aware of how much bias can mean. My bias was completely and fully on the side of the SMSL. It is 11 years younger, has a great NEW DAC, has rave reviews and meassures near perfectly, as I read on this website. I thouroughly absorbed ALL this information before purchasing the unit. I was honestly flabbergasted by the results I got.
bought SMSL D1SE2 and Singxer SA-1 V2 cause the stellar measurement in ASR for my hifiman HE1000 stealth and Focal Radiance. The sound was okay,it was clean and clear, nothing special.
after sometime i feel like this is not a sound that i want, so i sold the dac and amp.
then i used back my spare Audio GD Compass 2 bought backkkk from 2014, plug it to my HE1000 and voila what a surprise, bass kick improved a lot, soundstage came back, everything sounds more dynamic and alive, i cannot believe this, it is quite obvious the WM8741 and amplifier stage does a much better job at driving the HE1000.
To be fair tough, on Focal Radiance, the old setup was better, it was more detailed. the audio GD sure lose in technicalities, but it give you more natural sound which works wonder for sometimes harshly mixed pop/rock/edm that i like.
so TDLR.. i think tonality trumps everything else.i do not know what secret sauce audio gd put there.
now they have new AIO R29, and i am thinking hard between this and Hifiman Serenade.