Hello Chintan,
I assume you are referring to the Report Viewer web part for SSRS. This web part is designed to connect to SQL Reporting Services and display SSRS reports on a SharePoint page. This web part is not installed in SharePoint by default - it is installed
when you install SSRS on the SharePoint server.
The Data View web part is installed with SharePoint by default and allows you to connect to any of the following types of data sources:
· SharePoint Lists
· SharePoint Libraries
· Databases
· XML Files
· Server-side Scripts
· XML Web Services
· Business Data Catalogs
· Linked Data Sources
The two web parts are similar in that they can both show data from a data source in SharePoint, however the main difference is that the Report Viewer is meant to be used with SSRS reports, while the Data View web part is meant to be used as a stand-alone data
view. Another difference is that the view in a Data View web part is designed in SharePoint Designer, while the view (report) for the Report Viewer is designed in SQL Report Designer. SSRS is typically more powerful than the Data View web part,
so if you have SSRS available and you need the additional features it's better to use that. If you don’t have SSRS available and/or you don't need the additional features that SSRS offers, you can use the Data View web part. It really comes
down to what you have available and what your requirements are.
You can find more information regarding SSRS and its features here:
http://www.microsoft.com/sqlserver/en/us/solutions-technologies/business-intelligence/reporting-services.aspx
Thanks!!