I have a Lumin T1 but I can honestly say both the Roon and Lumin app sound the same to my ears. Went with Roon because of its better integration with Tidal and the fact I’m running Two other zones which needed a single control program
I use a Lumin U1 mini and have compared Roon and the Lumin App. I find the sound quality in Roon to be much better. I do find Roon to be frustrating to use, particularly for classical music. But the sound quality and Tidal integration make it worthwhile.