Science 3.0 needs a facelift before I can switch away from FriendFeed:
It comes down to the fact that the website has way too much information, and uses way too much space for things that do not matter. The interesting content only starts half-way my screen. I tend to have given up finding the interesting bits by then.
But even within each thread there is room for improvement. There too, there is abundant whitespace, though that might prove functional when the layout becomes more compact. Also, I life the photo of the people whom I follow to be removed (something that is done with a userscript only on FriendFeed too!). Instead, it should be clear where to thread comes from. (Regarding that, I am not sure if any RSS feed you can now list, will actually show up in this activity stream yet.)