As you might expect, Mufin’s iTunes add-on analyzes the songs in your iTunes library to suggest new music. While you’re playing a song, or an entire playlist, Mufin recommends new tracks simultaneously in the sidebar. You can then play 30-second previews of the new recommendations, and purchase them in iTunes if you enjoy them.
Since Mufin’s recommendations are based on properties like tempo and rhythm, the suggestions are a bit different than what you’d get with iTunes’ own Genius Sidebar, which performs a similar function.
Meanwhile, Mufin for Facebook is essentially the same application that the company launched on MySpace during their private beta. You can search Mufin for specific artists and tracks, and then have the service recommend new music, all within the Facebook interface. When you “discover” a new piece of music, that action is broadcast to your mini-feed. You can also send a song to your Facebook friends.
So is Mufin worth the download? I’m not blown away by the recommendations so far, but they are distinctly different than what you’d expect to see with a “people who liked this also liked” type list, or what you might see in browsing social discovery engines such as iLike or Imeem.