I was trying to find a good way to set up some shared calendars...one for my wife's work, one for my work, and one "family" calendar. Tried Sunbird and kind of liked it, but Google has quickly replaced it.
The interface is very intuitive, and drag-and-drop-ability is very smooth.
I wish I could find a good way to import/export, since the place I work uses MeetingMaker, and they really wish I were using it too.