Comparing Crystal Reports for Enterprise 4.2 vs. Crystal Reports 2016?

What is the feature gap between Crystal Reports for Enterprise 4.2 and Crystal Reports 2016? In other words, what features will prevent a Crystal Reports 2011/2013 report from being converted to CR4E after a BI 4.2 upgrade.

Also, I'm having difficulty getting customers interested in Crystal Reports for Enterprise. What are the benefits to using it over CR20xx?