This Snow Leopard Developer Preview Update is recommended for all users running the Snow Leopard Developer Preview Build 10A394 or later. This update includes general operating system fixes for stability, compatibility, and security. The update is 1.31GB, through Software Update, & I don't know personally what physical, in your face updates it brings, as its currently downloading. Updates: - Third party System Preference panes now work - New list view in the Dock - Quicktime Version 10.0 (42) - Battery on notebooks improved. - Safari is snappier (really!) - Overall system performance boost.