Azure AD Sync Beta 2 includes new features, scenarios, troubleshooting tools and improves stability.
New in Beta 2
- Selective synchronization which enables you to only sync attributes required for the services you want to enable
- AD password reset with multi-forests
- Exchange hybrid deployment in multi-forests environments which enables you to have mailboxes in Office 365 as well as in your on-premises exchange
Sign up for the beta here.
More details can be read in Alex Simons post on the TechNet Blog