This is in a response to a question on twitter:
In general, for applications, I would always use NHibernate. Mostly because I am able to do so much more with it.
For one off utilities and such, where I just need to get the data and I don’t really care how, I would generally just use the EF wizard to generate a model and do something with it. Mostly, it is so I can get the code gen stuff ASAP and have the data working.
For example, the routine to import the data from the Subtext database to the RacconBlog database is using Entity Framework. Mostly because it is easier and it is a one time thing.
I guess that if I was running any of the tools for generating NHibernate model from the database, I would be using it, but honestly, it just doesn’t really matter at that point. I just don’t care for those sort of tools.