Responding to some questions asked above...
I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp. I have no doubts about how they sound to my ears with my gear. They suck!
They are anything but accurate in terms of frequency response and poorly resolving of fine detail. And I've tried using them with numerous opamps in the buffer stage, including dummy buffers, which always provide the clearest impression of what's happening in the input stage.
I personally prefer my DACs and Amps to be neutral and clean. If I want to add color, I do it by switching headphones. The Muses02 just has too much personality for my tastes.
Surely, there are people who would love what I'm hearing with the Muses02, so there's no right or wrong here.