Surprisingly, Google has already rolled out Android N Developer Preview images (download) as well as offering it officially via OTA update through Android Beta Program for Nexus lineup including Nexus 6, Nexus 9, Nexus 5X, Nexus 6P, Nexus Player, Pixel C, General Mobile 4G (Android One). What makes this surprising is rolling it out before the Google I/O which is the actual usual time of Google doing something like that in past.
So, if you are Nexus user, you must try out Android N because it comes with so many interesting new features which are as follows:
Android N brings native Multi-Window support. You can use two apps simultaneously in split-screen mode, either up and down, or side by side. It also lets you change the app size (small or large) by simply dragging the dividing line.
Reply within Notification:
You can reply to the new incoming messages directly from the Notification area conveniently and quickly. No need to leave your current screen or app.
New Data Saver:
With Android N, you now have complete control on Data. Once you enable the Data saver, you can choose which apps to use data and which not. By white listing the apps in enabled data server, no other apps will have access to the metered data.
more updates coming..