I did some remote LAN listening testing with Roon Arc.
Results were mixed. When the connection worked the sound was good. That was in the am. In the afternoon Roon arc indicated a weak connection and nothing much would stream. Meanwhile Plexamp worked perfectly as usual the whole time.
So looks like Roon still has work to do for remote streaming. The problem seems to be Roon Arc does not appear to downsample the music to match the bandwidth of a slower remote connection Plex does this well and delivers good sound via headphones at lower res with no problem. Plex is just better designed to deal with lower bandwidth network connections than Roon it seems. But at home, on the local LAN Roon sound quality rules.
Plexamp is also still more versatile when it comes to downloading music files so no network connection is needed. It handles downloads of playlists as well as albums . Roon Arc does not appear to handle download of playlists yet.
I use remote streaming from work quite a bit so looks like I will hold on to both Plex and Roon for now. Plex is inexpensive compared to Roon and still represents a good lower cost option overall or a good complement to Roon for remote streaming .