I'll spare you the marketing, here are the three links you may be most interested in.
The release notes are here:
MOST important – what's new:
I'd like to mention a few more things which I'm excited about:
The multitenancy support is awesome, so is the depreciation of isinteg allowing individual mailbox repairs, so is the installer installing the required dependencies, so is public folder client permission support being added to the ECP, being able to reset a single virtual directory from a cmdlet, faster owa, etc,etc.