Selecting the categories on the left doesn't do what it's supposed to, just nothing happens at all. Otherwise, it's great to see the Labels are finally here, but they're currently useless due to the aforementioned bug. About the interface - the green and blue progress bar colors (both in columns and in the General tab) are way too much in your face, too intensive and plastic-looking. A more translucent look would be more pleasing (like the green lamp that indicates the port is open). I like the tabs in general, although the old design was better in my opinion. The icons on the toolbar are definitely not looking good. Old ones were just ok. I mean, look at Safari, Mail, or even Firefox for Mac. Their icons are in harmony with the grey window frames and toolbars. These bright colorful buttons just don't blend in nicely, they look like some Firefox skin for Windows. A mouse-over effect would be nice too (see Mail.app).