I read this article on Linux Music Players so I decided to install most of them and compare it to JRiver.
http://thesimplecomputer.info/choosing-a-linux-music-player/None of them were even close to the functionality of JRiver. JRiver rules and it is still early days for the Linux port.
I only needed to spend 5-10 mins on each one because if a player is missing basic functionality, then it is a no go. I consider basic functionality to be:
Hierarchical View - Genre/Artist/Album Pane
Can view and edit all tags.
Preserve integrity of tags (don't convert to all uppercase or lowercase)
Multiple Libraries
Here I outline each player and what basic functionality it was missing
Clementine, Amarok,
No Hierarchical View - Genre/Artist/Album Pane
Could not view all tags
Converted tag names to all uppercase
Only one library
Audacious, DeaDBeef, Exaile, Juk, Rhythmbox
No Hierarchical View - Genre/Artist/Album Pane
No tags
Only one library
Guayadeque
Could not view all tags
Converted tag names to all uppercase
QuodLibet
No Hierarchical View - Genre/Artist/Album Pane
Converts Tags to all lowercase
One Library
Gmusicbrowser was the only browser that met all the basic functionality. It does tag editing better than JRiver because JRiver converts some tags to all uppercase. But JRiver is far more feature rich overall.
The only thing all the other players did better than JRiver is the GUI integration with the desktop is smoother - native (nicer) fonts, re-sizing works properly.
JRiver is currently the best Linux option and it will only get better over time.