Apple unveiled their latest mobile OS, iOS 7, at their World-Wide Developer Conference last June 10, 2013. The new iOS 7 came with a departure from the tried and tested iOS look-and-feel. Gone are the skeuomorphisms and in its place, a more 2D UI design. The 2D UI design comes with a layered implementation that provides depth to the overall user experience. The depth of the new UI is evident when you encounter graphic elements that pop up as overlays -- you will have a view of what is beneath the overlay, providing you with some feel of context.If you will believe what others have said about the new UI, the iOS 7 borrowed design elements from the likes of Windows Phone, WebOS and Android. However, just as always, Apple (re-)uses existing technologies (and in this case, design), polishes it to perfection, melds it with their products and adds some fairy dust before it is released. Whilst you will say that they copied this and that from this and that phone, remember that Apple recognizes the best and steals them (great artists, remember?). Say whatever you want, Apple's bottom-line is they perfected these technologies and tried to make it disappear, i.e., when using the device makes the underlying tech disappear, then they have achieved perfection.
I have read comments from writers with sources from within Apple and one word stuck with me -- polarizing -- that the new iOS 7 look-and-feel will have that polarizing effect. And it's indeed polarizing - you either love it or hate it. :) There are stuff to hate, such as the look of some of the icons, the background of the app folders and the predominant use of white spaces, there are a lot to love about it -- Control Center, Notification Center (with some actionable notices), Multitasking, iTunes Radio, revamped Photo gallery, AirDrop, revamped Camera, new Safari interface, enhanced Siri, enhanced Mail, enhanced Calendar and enhanced Messages (and more actually).
It should be understood that at its current form, iOS 7 is still in beta, beta 1 to be precise. There is a reason why it is only available to developers -- because what matters to developers is the underlying architecture and the APIs. Unfortunately, I cannot give you any other details, except for screenshots similar to what Apple has shown but shows iOS 7 on a real local device, due to the NDA.
Apple's new iOS 7 will undergo changes before it gets released sometime September or October, along with the next iPhone, and perhaps the new iPads. In its normal cycle, iOS versions tend to go up to beta 7 before the final GM, or Gold Master, version is released to developers. And the road from beta 1 will be paved with numerous changes -- from design (color scheme, icons, etc.) to implementation (how a button behaves, API behavioural changes, etc.). Note that Apple has not yet provided an iPad version of the firmware -- they will perfect the iPhone first and then it will be simpler to scale it up to the iPad.