The Report Viewer lets you to view all stored reports locally from a Windows workstation. Because the Report Viewer utilizes the resources of a Windows workstation, rather than those of the Engine, the Report Viewer can display stored reports much faster in most instances.
The Client Tools are designed to provide members of the administrators group expanded abilities in designing reports and analyzing data. The Client Tools include the Report Designer and the Analytics Tools.
NOTE:You must be a member of the srsadmins group to use the Client Tools. The name srsadmins is the default name (which you can change) of the File Reporter administrators group created during the installation of the Engine.