This beta release includes a few forgotten features or features I didn't have time for, or features submitted by users that were too good to pass up. Plus, a lot more of the help files are written, if badly.
Specifically: comment RSS, major updates to exposed filters, a bunch of new default views, important fixes for node language filter, taxonomy term with depth argument, argument defaults to try and get 'node' and 'user' ids automatically from the URL, and a whole bunch more I have forgotten.