I’m pretty impressed with what plex manages to do – I’ve only started to scratch the surface. Just with audio. Its pretty amazing for video too, but I’m not yet putting that library in until I have some terabytes of storage available.
But just with music – its ability to download album covers and lyrics to integrate with the music database (I’m using iTunes/music as the basic library) – its really impressive.
Plus Sonos can use it directly (unlike Apple Music) without a host computer streaming sound to the Sonos. Much better than airplay in my view.