Sync 2.0 is out, and looks pretty damn good.
All of the core functionality we introduced in version 1.4 last August still exist in 2.0, letting you securely share folders across all platforms, with visibility into who has access.
A bunch of new functionality has been added, from enhanced user interfaces across desktop and mobile platforms to a new certificates-based security model with even greater control and ease-of-use. Go here to check out all the many new features in Sync 2.0.