Persistence maps stored procedures to objects and back. No configuration. Field name mapping is done inside the stored proc. While Table-->Object mapping is available, it is Stored Procedure-->Object mapping so is more flexible.
Most systems become Lists and Items.
LINQ can be used on the Objects in memory rather than querying the database.
Referential integrity is enforced by the database, so no referential integrity information is stored in the application/business logic layer. This allows the developer to focus on the business problem rather than the tables, rows, and columns format required by the database and reflected into most ORM systems.
The other advantage is side-by-side development. Persistence works with ANY database. Generate the basic stored procedures and classes and any application can be rewritten one screen or page at a time without disturbing the existing application.