Aside from a handful of new features, generally, the report design experience is unchanged.  Things got a bit confusing in SQL Server 2014 when the database project template and the Business Intelligence project templates were both given the name “SQL Server Data Tools”.  At the same time they came in separate download packages for different versions of Visual Studio.  This confusion gets sorted out in the new product version; currently, the SSDT package now includes the whole kit and kaboodle: database and all BI project templates.  In the near future, SSDT will be managed outside the SQL Server installation so you should be able to use any version of Visual Studio without worrying about which SSDT package to download and install.

Report Builder is updated with a modern look-and-feel, simple and sleek.  Changes are mostly cosmetic while the fundamental features are the same.