Report Builder is a report authoring tool within Microsoft SQL Server that features a Microsoft Office-like environment, giving the business user the possibility to author existing reports or create new ones. All the objects such as tables, tablix, spark lines, gauges, … from Reporting Services are available for the business user and can be used in a user-friendly environment.
The development works in 2 ways. Reports build in BIDS (BI Development Studio) can be customized in Report Builder and vice versa.
BIDS is intended for the developer and has more advanced features where Report Builder is intended for business users so they can customize reports to meet their needs.