iTunesFS for Mac enables you to explore your iTunes library in a novel way, by treating it like a bunch of nested folders. Not only can you use it as a replacement for iTunes, but also to manage mobile devices that aren't iTunes compatible. It's a really promising app.
iTunesFS for Mac requires you to install the MacFUSE framework before you can launch it. However, we were unable to run the app on OS X Mavericks, as it just wouldn't launch. We did manage to test it on OS X Mountain Lion and it performed well. Launching it allowed us to find another mounted disk in Finder: the iTunes library. While browsing, we were able to update a playlist by removing a song and copying another. In the app's main window, which looks somewhat dated but clear to understand, we also tested the ability to view an iPod's library as a file system and extract a single song from it. The extraction process took about five seconds for a three-minute song.
If you're tired of the limitations of iTunes as a music manager or own devices that aren't compatible with it, you'll really like iTunesFS for Mac. The ability to extract individual songs from an iPod that this app offers makes it stand out from other similar apps. Whether or not it can replace iTunes is something that you'll have to decide on your own.