I didn't use basecamp before and I'm just testing a little bit. Seems to be quite fast. What I kinda don't like: If you click on e.g. a discussion, a modal-window-like layer pops up where the discussion is displayed. Now how can I go back? First I was quite unsure how to do this without clicking on the browser's-back button. Then I figured out that you can click out of the layer and the layer disappears. I think there's a need for a "close"-Button..