Is it easier to go from LinqToSQL to EF4.0 or EF3.5 to EF4.0?

Now that Entity Framework 4.0 is coming out I was wondering, if you were planning to use EF 4.0 when it is released would it be easier to 开发者_开发技巧go from LinqToSQL to EF 4.0 or EF 3.5 to 4.0?

In other words if you were starting a project now anticipating using EF4.0 would you use LinqToSQL or EF3.5 now?

It will be easier to migrate from EF 3.5, because many parts of the code will be common. It still will be a lot to do, because if I migrated to EF 4.0, I would propably switch to code only design. Why do you limit yourself to EF and Linq to SQL? There are other solutions: Subsonic, nHibernate. They are more mature, thought through and well tested.