Mission Control unifies Snow Leopard's Exposé, Spaces and Dashboard functions into a single feature. And it's magnificent. Accessed through a function key, a Dock icon or (best of all) a simple three-fingered gesture, Mission Control gives a birds-eye view of everything that's running on your Mac.
Open windows are grouped according to application, so you can quickly and easily navigate to the one you're looking for. Across the top of the screen, your Dashboard, Full Screen applications and Spaces desktops are shown. In effect, the top section of the screen replicates Snow Leopard's Spaces function and the lower half becomes Exposé.
And integrating them on a single screen enhances both. If your desktop is getting cluttered, it's really easy to open Mission Control, add a second desktop and drag windows from your main work area to the secondary one.
Individual Exposé functions such as Application Windows and Show Desktop are still available, and can be accessed through the function keys as before, or through Gestures. You can configure the keys through the Mission Control preference pane, and the Gestures through the Trackpad pane, but the default settings are more than comfortable.
BRINGING IT TOGETHER: Mission Control is a useful and comprehensive fusion of Spaces and Exposé
Our only criticism of Mission Control is its aesthetics. It's far from attractive, and definitely not up to Apple's usual design standards. Perhaps the means for adding a second desktop could be clearer too; you hover over the right-hand side of the Spaces row until a plus sign appears. If you didn't know, you would never guess. Even so, Mission Control is an exciting addition to OS X, and significantly simplifies the way you interact with your Mac.
The Mac App Store was introduced with OS X 10.6.6, but is now built into Lion, and brings a handful of new features. In-app purchases are now catered for, as are delta updates, whereby when updating an application bought from the Mac App Store, only the sections that have changed are downloaded.
Push notifications allow developers to bring you important information about their app, even when it's not currently open on your machine. For security, Lion also greatly enhances OS X's sandboxing function, something Mac App Store downloads will soon be required to use.
APP IT UP: Lion's Mac App Store offers new features