Anyone using Entity Framework in a production environment?

When studying up on Entity Framework I have to wonder whether this is ready for building Enterprise applications (i.e. large scalable production environments).  I am curious because we are going to decide soon on standardizing our data access / ORM technology. 

My question to the community is, does your organization, or any organization you know, use Entity Framework in production?  If so, how many concurrent users can it support?  Also, I would like to hear any good, or not so good, experiences.