A couple of points here. I know Bill and he is usually spot on with respect to how things sound. He states the MU2 is excellent. His point about the MU1 and separate Tambaqui is that if you use excellent power cables and interconnects, the separates are better. True, the MU2 also has volume control, but in his world, he is using an amazing preamp which is better again. So for price and one box convenience, go with the MU2. For absolute best sound, go with the separates and use good cables. BTW @jjgasp, both the MU1 and the MU2 serve as Roon core and Roon endpoint.
Grimm MU1/Mola Mola Tambaqui combo vs. Grimm MU2
Here is a great video discussing the very popular question of which is better: the Grimm MU1 streamer with the Mola Mola Tambaqui DAC or the Grimm MU2 with built-in DAC?