I've now had the MP-D2 since January and am extremely satisfied with SQ.
My previous DAC history encompass Cambridge DAC1, Audio-Lab MDAC, Audio-GD Ref-5, iFi iDAC2, AMI Musik DS5 ... and some DAC's I may have forgotten.
Prior first power up of MP-D2 I installed following:
Rectifier tube: BRIMAR NOS 5Z4GY/CV1863 (Coke bottle)
Signal tubes: 4x MATCHED 6N23P 6Н23П VOSKHOD
Capacitors: Mundorf Silver/Gold 2,2 uF
My setup looks as follows: Norma Revo IPA-140 integrated amplifier, Gauder Akustik Arcona100 Speakers, MediaPC w. Roon.
Upgraded MP-D2 firmware to version 10-6 today, can't say I noticed any difference.