When FeedDemon updated to version 3, it stepped in a snarling nest of controversy because the popular RSS and Atom feed catcher was abandoning its online synchronization Web site in favor of Google Reader. The new FeedDemon 3.1 is a good effort to move beyond that, introducing new multiple new features that mostly bring it into parity with Google Reader.
The two biggest new features include on-the-fly item translation via a translate button on the individual item toolbar. If the item is in a feed that you synchronize with Google Reader, the translation will occur in-line. If the feed isn't synced, then FeedDemon will open up a Reader page. There's also a new content filter that lets users create filters to automatically certain kinds of incoming items as read. For people who subscribe to tens or hundreds of feeds, this can potentially be a major time-saver.
There's a new "Shared by people I follow" option under Shared Items, which syncs shared Google Reader items. FeedDemon goes a step further and adds in a social component to find people to share with. You could type in "politicians in San Francisco" and, theoretically, get Mayor Gavin Newsom. Users can also now customize by feed the icons that appear on the item toolbar, and this includes adding a Google Reader-style "like" icon. It's not enabled by default.
The list of short URL previews that are supported has been expanded to include goo.gl, youtu.be, fb.me, flic.kr, ow.ly and clicky.me, and the Send To option now includes Twitter.
The official release notes indicate performance enhancements, but my experience with version 3.1 was that there was still plenty of room for improvement. Even 3GB of RAM didn't prevent occasional program hang-ups. However, FeedDemon creator Nick Bradbury pointed out that the database can be massaged into being quicker by regular compacting. This can be accessed under File, then Manage Cache, then Compact, but it's a cumbersome thing to have to do semi-regularly and without a scheduler.