Looks a lot like iTunes 10. And … the bug I opened in 2008 is still there! Sweet. Sort your library by Album/Year, and then reverse direction (year descending.) Reverses album order. E_WONTFIX.
There's no sidebar for quick access to things, you have to click album art to select a song, etc. It's a very large UI departure. You can return it to more normal though by viewing by "song" and then selecting View > Show Sidebar.
It hasn't added any useful metadata features. It doesn't appear to cache the downsampled synced versions of music. The default view is different, but it's trivial to get back to the well understood two/three pane layout. There's more iCloud stuff. The "Up Next" feature is pretty nice.
A lot of visual as well as functional features has been added (see http://www.apple.com/itunes/whats-new/). And the iTunes store has been redesigned as well.
