Entity Framework vs NHibernate

I have worked with both Entity Framework (at work) and NHibernate (at private projects) for a while now, and I tought I would write a post about the differance between the two. They are both (kind of) Object Relational Mappers (ORM´s) and they were developed to solve the same problem, that is data access in a .NET application. Entity Framework is a product from Microsoft while NHibernate is a Open Source project.