The MU1 sounds amazing with my MM Tambaqui. But it is not as yet functional as a Roon endpoint ONLY. Per my conversations with Grimm, it soon will be. This is really only an issue if you have two systems, where one runs Core and the other needs to be endpoint only.
Nice posts. To be very clear regarding the above quote, the Grimm will feed Roon endpoints on your network just as any other Roon core server and the device/dac connected directly to the Grimm receives the proprietary optimized feed. In other words, I have the Grimm in my main system feeding my main dac and the other deivces/systems around the house serve as Roon endpoints from the Grimm.
Im not sure why anyone would want to use the MU1 as an endpoint only however I suppose a $12k upsamplers/optimizer Roon endpoint isn't out of the question in our hobby.