The value of Roon goes beyond just integrating your local library and Tidal (which it does very, very well). There is an ease of music discovery and learning about the musicians that has been talked about, but would hard to not have, now that I have experienced it. I have been exposed to so much new music that I love in the year I have had Roon.
Also there is a step-up in sound quality (SQ) from iTunes. I would say the SQ is about the same as what I was getting with iTunes+BitPerfect ($9.99;
http://bitperfectsound.blogspot.com/). Adding BitPerfect to iTunes gave a very noticeable jump in SQ and easily worth the $10.
Given that I was running my Roon core on a MacBookPro (MBP), my reading suggested that I would get better SQ going to a dedicated server. In the interest of user ease and install, I bought a Roon Nucleus and it was super easy to get up and running (plugged an external Samsung T3 or T5 SSD with my iTunes library in via USB) and flawless in use over the last year. The sound was identical to iTunes+BitPerfect on the MBP, except the noise floor was noticeably lower. This might not sound like much, but actually is. You hear more of the acoustic space of the recording, you hear more of end of the notes, you hear more of the small variations in the notes themselves, and gain more of the expression of the musician. Really quite remarkable. I am wondering how much further I could improve this aspect, so I am going to purchase a LPS for the Nucleus, and if that improves SQ (it pushes USB directly into my Yggy), I will get LPSs for my cable modem and router.