Crystal and RDLC Reports- issue in iis server

Hi all...

I want to ask few queries -

For generating any report in asp.net for any portal...

1. Crystal Reports and RDLC Reports do not run properly on iis server. Why is that so ??

2. Other approach is - write all queries in database, call the stored procedure from front-end and attach the datatable on gridview.

Which one is better ??

What are the limitations of Crystal Reports and RDLC Reports ???

Are they a good approach to Reports in asp.net ??

Do Crystal Reports and RDLC Reports support iis 7??