I discovered Gruml a while back, but didn't write about it right away because there were too many glitches in the first beta to make it really interesting. Thankfully, recent releases have smoothed out the vast majority of the kinks, and I can now present -- with gusto -- a great RSS reader that interfaces with Google Reader.
NetNewsWire switched to syncing with Google Reader back in July, and I was pretty excited. Google Reader has been an amazing tool for me in the RSS world, and the more apps I have that all sync with it, the happier I am. However, despite seemingly endless trials and searches, I haven't really found the app that can top a Fluid SSB with a good userstyle. Gruml comes the closest so far, and it's free (at least right now, I'm not sure what the future holds after beta).
One of the things I like about desktop clients (when it comes to RSS readers) is scriptability. Gruml currently lacks the AppleScript dictionary that, say, NetNewsReader has, and I'd love to see it implemented. The keyboard navigation is decent, but not yet up-to-par with Google Reader's web interface, which can be navigated entirely with the keyboard. It might not make a difference to a lot of folks, but when I'm cruising through headlines I like to be all-keyboard when possible. The "Send Article to ... " menu is fantastic, covering 12 services ranging from Delicious to Twitter, and including Facebook, Ping.fm and Posterous. Note-taking, starring and sharing are all very well done, and sync perfectly with Google.