>>>>http://ayende.com/Blog/archive/2010/01/05/nhibernate-vs.-entity-framework-4.0.aspx
>>>>
>>>>There isn't much of a comparison. Microsoft should just scrap EF and adopt NHibernate as their official ORM solution.
>>>
>>>Terrific. I just received an EF book from Amazon yesterday, planning to read it on the train. Maybe not the best investment of my time at this point?
>>
>>Hi,
>>
>>I'd take the info on Mike's link with a pinch of salt (not a large pinch, but a pinch nonetheless) - NH may be better than EF (I'm not qualified to judge) but EF is not as inferior as implied. Also, there are a lot of new features in EF4 that, AFAICS, weren't really taken into account in that assessment.
>>And that syntax I posted (copied from the link) looks horrific. I might be wrong but the argument that NH can produce more optimised SQL seems to be based on the fact that you have to tell it exactly what to do using very convoluted syntax.
>>
>>What book do you have - I'd guess Julia Lermans?
>>If so I'd say it's a good book but in danger of making EF sound more compicated than it need be for general use.
>>
>
>Yes, Julia Lerman.

OK. As above don't let the detail overwhelm you (g).
(a) It covers 'Linq to Entities' (including method based queries) and 'Entity Sql' - knowing only one of these will be enough 90% of the time.
(b) Although whole sections of the book are devoted to tweaking the EDMX models you will probably find few occasions where this is needed in practice.
(c) EF4 will also optionally give you EntityObjects with disconnected change tracking so another whole subject is moot.

TBH I'm still working through the deeper parts of the book - but given the changes which will be in EF4 I'm not sure it's worth it.....