I'm loving 4.0 beta 4, it's extremely stable, more or less RC. But I think Apple is missing a great opportunity. In the new Task Manager Switcher Dock, instead of app icons, you should see small thumbnails of the apps "saved state." Apps that don't have a saved state, or aren't 4.0 compatible should be an app icon. IMO, this is a no brainer?? Would be way more useful.