Here are the some features:
-News App
-Updated Notes app (like on OS X El Capitan)
-Transits in Maps
-Apple changed the Passbook app to Wallet app
-Changes in CarPlay
-Split Screen Multitasking on the iPad Air 2
-Slide Over on iPad Air, iPad Air 2, iPad Mini 2, iPad Mini 3
-Picture in Picture on iPad Air, iPad Air 2, iPad Mini 2, iPad Mini 3
-Shortcut bar on iPad
-Updated Siri UI
-Proactive Siri
-Low Power mode
-Smaller update
My Review:
I love it. It has some really good new features. Only thing that could have been much better is split screen multitasking on the iPhone. Jailbreak tweak called ReachApp confirms that this can also been done on the iPhone. Other good thing about it is the fact that it's much smaller ota update. I am really excited for the final release on September.