Well it's been a long time since you posted, but I have used the Java Mod Player quite a bit. It's not perfect - sometimes it refuses to play a song and throws an arcane Java error in tiny text at the bottom of the window. Otherwise functionally it seems pretty good. I do have a few quibbles with some songs that don't sound quite right, but I'd say 95% of the time it's very good. I like that it is a portable chunk of Java - the modularity of that is nice. No install necessary. The GUI sometimes doesn't behave well if you mess with the size of the window.
There, that's my feedback.