Update, 6/21/2016: Be careful using indirect checkpoint with failover clusters if your SQL Server 2014 instance is not fully patched. See KB 3166902. This bug was fixed in SQL Server 2016 prior to RTM.
SQL Server 2016 introduces big new features, but it also includes small improvements as well. Many of these features are described in the “It Just Runs Faster” series of blog posts by Bob Ward and Bob Dorr.