F# - Which ORM to choose?

This may be missing the point (like if this is just for education or fun), but if you already know how to use an ORM in C#, why not just do it in C# as a library and then do the rest of the logic in F#? One of the major selling points for .NET languages is interoperability.

I've been using F# support for LINQ to SQL when working on fssnip.net. It is fine when you need to load, edit, insert entities and it is fine for writing simple queries. It has some nice aspects e.g. you can use splicing to compose parts of a query.

However, the current implementation of F# to LINQ translator doesn't handle complex queries (nested function calls, advanced grouping and joins), so I wrote a few stored procedures. These can be nicely called via generated LINQ objects, but you have to write some SQL.

Alternatively, if you wanted to use the old fashioned SqlClient, you could make it nicer by using the dynamic (?) operator. I wrote about this in this blog post. For simple scenarios, this could be quite good technique, because it is very simple.