When comparing Nightingale vs Mopidy, the Slant community recommends Mopidy for most people. In the question“What are the best audio players for UNIX-like systems?” Mopidy is ranked 33rd while Nightingale is ranked 48th. The most important reason people chose Mopidy is:
Extensions permit the streaming of music from cloud services such as Spotify, SoundCloud, and Google Play Music.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Nice Coverflow add-on
Pro Good library organization
Pro Highly customizable
Pro Skinnable
Pro Capable of streaming music from cloud services via extensions
Extensions permit the streaming of music from cloud services such as Spotify, SoundCloud, and Google Play Music.
Pro Many front-ends
MPD clients and HTTP extensions/clients can connect to your Mopidy server. Front-ends range from web front-ends, mobile applications, to even console clients.
Pro Available as a Docker file
Mopidly's Docker file can be found here allowing for quick setup.
Cons
Con Basically Abandoned
There hasn't been an update since 2016 as far as I can tell. The forum's dead, and the las blog update was in 2015.