Well I have been using ARC for a last few months. I love using Arc especially now with CarPlay but I have some of the following issues that I don’t have with PlexAmp:
1.Frequently I have to sign in to Roon
2. Doesn’t remember where you left off on a personal playlist
3. ARC doesn’t like large playlists.(PlexAmp I can play my whole library 70k + songs) playlist lot less
File tagging is excellent on Roon/Arc better then Plex
I am hoping for improvements and some add-ons like Siri or Google assistant support. And ability to shuffle or repeat now playing screen on CarPlay.