I have over 21,000 Albums in my library.I'd like to comment on the idea that Roon is good for people with large libraries:
The iOS and android Roon Remote apps have no way to quickly scroll through albums. There is no "alphabet slider" on the side like basically every other music app has.
So, if you like to browse by album and have 500+ albums in your library, you will be swiping 30-40 times to get through your library from A-Z.
Lots of people have complained to Roon about this for over a year, but they've done nothing to address the problem other than suggest typing in the name of the album you want to hear, which isn't the same as "browsing". I have 1000+ albums ripped from CD and can't remember the titles of all of them. So i like to flip through and browse to find a forgotten album once in awhile. Tedious and painful on Roon.
Roon is great as an automatic jukebox app and as a Tidal controller, but I've gotta say, for people with big collections that they like flipping through and browsing, it's just badly designed for the purpose. I was excited to switch from Plex to Roon, but after 6 months, I've switched back specifically because of this.
Also, I'll mention here that things seem to break frequently on Roon. An update a couple months ago kills functionality on QNAP devices, for example, and they have a non-employee community member working on the fix instead of doing it themselves (!)
Previously, playback on most Android devices stuttered like crazy and had random, loud static pops and cracks that could damage your hearing. It took a couple months for that problem to get fixed, too.