Azure AD Connect retires Azure AD Sync and DirSync, so Azure AD Connect have been in Beta and is now in Public Preview. Allthough the download link seem to be dead (Page not found).
I want to point out a New feature, which is a wizard Automatic installation and setup of SSO (ADFS 3.0/WAP) With Office 365. It makes the entry Level for Single Sign-On lower, but we still need to judge if we need SSO and will take the extra cost to host SSO.
Azure AD Connect will ofcourse support Password Hash Sync aswell, which is less cost to host than SSO, and browsing Office 365 is the only feature supporting SSO. While Outlook, Lync and OneDrive requires us to provice our password aswell as username.
Source: Technetblog by Alex Simons.