This is a confident design where all of the elements hang well together.
The feel of it
From the moment you hit the home button and the lock screen pops up, you'll notice some different, but subtle, changes. When the display comes on, for instance, instead of snapping into view, it fades to life. And when you turn the device off, the screen fades to black.
There is a distinct feeling of depth throughout the OS, a reflection that the user interface has been sectioned into layers. Nowhere is that more evident than with the use of parallax for home- and lock-screen backgrounds; depending on how the phone is held, the background image shifts beneath text and graphic elements. It delivers an almost 3D experience, and was showcased during the WWDC demo.
Unlocking the phone using a swipe-to-unlock gesture is no longer limited to a specific swipe area. Swiping left-to-right anywhere on the screen fades away the lockscreen, fades up the home screen background, allows app icons to glide into place, followed by the lower app dock. All of this happens quickly, and plays into the overall "layered" feel.
Opening folders and launching apps now triggers a zoom-in animation that reminds me (geek alert!) of the level transitions in the game Flow (there's an example at the one-minute mark in this video -- or the animation used for the stellar cartography scene in Star Trek: Generations. Tapping a folder and launching an app zooms the content into full screen view, as if you're plunging into the folder or the app. Quitting an app and tapping out of a folder triggers a zoom-out effect.
Double-tapping the home button launches the new multitasking bar, which springs into view by pulling back on the on-screen interface, displaying app icons and a screen shot preview of recent apps, allowing you to swipe through them with now-familiar swiping gestures. From here you can quit background processes with an up-swipe gesture -- as if the app is being dismissed -- or you can tap to select the app and be plunged into it.
The Notification Center and Control Center panels are both accessed from their respective areas of the screen via different swipes, a top-down swipe or bottom-up swipe, respectively. The Notification and Control Centers look as if they sit in a layer that seems to reside on a higher plane than the multitasking interface; anything underneath it is blurred by a frosted glass effect. (That effect shows up throughout the OS.)
Between the parallax background view and the interface layers, the feel of iOS 7 is a very stylized attempt by Apple to give spatial orientation to the interface. However, the new design is no more confusing than previous versions and the use of text instead of icons in some spots actually makes it easier to figure out what you're doing.
Generally, iOS 7 retains much of the straightforward interface concepts that have helped make the iPhone and iPad so popular, but this release uses animations more effectively to graphically convey exactly what is happening. It's similar to some of the changes we saw back in 2001 in the move from MacOS 9 to OS X. While Windowshade had its fans, OS X's genie effect and Dock combo was an easy visual metaphor to grasp, especially for novices. The same is true here.