Gridview is the replacement in .net 2.0 for the datagrid.
the differences between them is >>sorting editing and 
paging are the additional capabilities in gridview which 
requires no coding while Datgrid requires the user 
coding .Gridview has improved databinding using smart 
tag.Additional column types and design time column 
operations.Customised pager UI using pager 
template.Customized paging support.

Datagrid has itemdatabound event but in gridview it is 
replaced by rowdatabound.In datagrid u can show more than 
one table with their relation while not possible in 
gridview.

Gridview have More properties and events than datagrid.
Auto delete,Edit,auto column,rowbound,rowdeleteing and many 
more.
Grid view is more user friendly than gridview.

datagrid is centralized by itemcommand property but 
gridview is not

Gridview have auto delete,Edit,auto 
column,rowbound,rowdeleteing and many 
more.

Datagrid is centralized by itemcommand property but 
gridview is not.

 Gridview have auto delete,Edit,auto 
column,rowbound,rowdeleteing and many 
more.

Datagrid is centralized by itemcommand property but 
gridview is not.
Grid view is more user friendly than gridview.

In gridview paging is also impletes by user

using gridview we can transfore the control one page to 
another page.ex..if i create one master page, and one detail
(child) . we can provide easily link from master page to 
detail(child) page.and transfer on that page. its a main 
benifit of using gridview , i think so........