You could have opened a big can of worms here. I have not had a lot of experience with ORM tools, I have used Linq To SQL in a small personal project just to have the experience. What I know about them I don't like. I am a huge proponent of doing data access and manipulation through stored procedures and many ORM tools make this difficult.

The positives of ORM tools from the developer side is you don't have to write a lot of SQL and the classes are built for you so you should get faster initial development.

The negatives are that the ORM tools usually don't provide the most performant SQL and make it hard to use stored procedures. You also have to change the compiled app to address many performance problems. You can't make changes to the database without making changes to the application. If you use stored procedures or views as an API (see today's editorial[/url]) to your database then you can performance tune the SQL more easily and you can make schema changes without affecting the application.

Just my 2¢ worth.