One thing I will say for Flock is that the News Reader could use a little work.
The minor. The autoviewing functionality is a little bit... difficult. It views a whole page of articles at once. Long before I've read them all AND the really long articles well it doesn't auto-mark them as read. No big deal you think. But if you're the kind of person who loves to see nothing left in your news reader to read, it can be a little frustrating.
The major. The number one thing that is really bugging me about flock's newsreader, is that it doesn't connect with Google Reader. I'm switching computers all the time, from work to home to the laptop and back. My choice is either, reading the news in flock means that I have to also go and "read" them in google reader or flock on any other computer. This isn't working for me.
I just deleted all my news feeds in Flock and hope, that at some point, Flock and Google Reader will make beautiful music together.
Until then you can find me at www.google.com/reader