Drew Jaynes announced the release of WordPress 4.2 Beta 1. In the post, he highlights Press This, Theme switching in the customizer, shiny (plugin) updates, and emoji support as the primary user facing features. There are some big developer focused features that need testing too.
Test, report, test more, etc. You know the drill if you're reading this. Congrats to the team on getting the release out. This is going to be another great release.