As a Plex and Plexamp user, I'm curious about a few features: mobile support doesn't seem to be mentioned. Is there a mobile app? Are smart playlists a feature? What about gapless playback? Can you elaborate on the 5 star system for rating tracks, albums and artists?
Overall the feature set really speaks to me, as I have a bunch of CD rips tagged using MusicBrainz Picard with a couple of deluxe and non-deluxe versions thrown in of the same album. I think I'll have to give it a try either way because you're touching on a niche Plex just doesn't seem to care about.