Properly label your ID tags and you can accomplish the same thing.
Rarely do I choose my music by attributes like "aggressive" "Happy" "Sad" etc.
Rather I enjoy listening to a few genres mixed together. Maybe Techno/Dance on one playlist or Jazz/soul vocals in another.
Moodlogic has been around a while. I believe it's creators actually worked for Apple at one time(at least a few of them)
Moodlogic sounds like a great product though. Just not too sure I'd pay money for it.