Recently,I did some researches for Entity Framework and LINQ to SQL. I found Entity Framework sounds better. It got better facilities. It can generate data tables from EDX and if the tables can generate the updated classes from the database. If you are using LINQ to SQL, you need to update manually. Entity Framework sounds a more completed ORM, LINQ to SQL is only a tool to translate the objects into SQL. But I think LINQ to SQL is more lightweight.