It's too early for me to compare.
I can only tell you that it's not a toy.
It's a solid DAC.
Works flawlessly both wired and BT.
Tested FLAC and DSD at various frequencies (only iPhone for now, tomorrow morning PC) without any hitches.
Sounds clear and defined.
Very very good.
So far I prefer it in NON TUBE mode; I can say that the two modes are not slogans: the difference is clear.
I think I hear a sort of crackling in TUBE mode + USB, but I need to make sure that's nothing else.
So far I can say that it's a great product, a big upgrade over the M4.