List of features available in 6.0.3
One answer
There is a long trail of new features between 4.0.3 to 6.0.3.
Start with the New and Noteworthy (6.0.3) and work down the version history.
One big operational change is Data Collection Component is required in 6.0.3. This replaces the data warehouse jobs that have been part of RTC since the early days.