SQL Server 2016 CTP2 is now available!
For those of you who want to watch it, it has been available for download since last week: http://www.microsoft.com/en-us/evalcenter/evaluate-sql-server-2016.
MS has also released Books Online for 2016 with a great What's New section for SSDS for those of you who want to immerse yourself in all the news.
Books Online: https://msdn.microsoft.com/en-us/library/ms130214%28v=sql.130%29.aspx
What's New: https://msdn.microsoft.com/en-us/library/bb510411(v=sql.130).aspx
/Björn