> At this point I'm convinced only MS know how to write LINQ providers that won't fall over the moment you try to do something useful with them.
I would argue Revenj + Postgres provide much better developer experience. But as you said, it's not written by Microsoft so that attitude doesn't help it out.
I'm 100% sure Microsoft can't write LINQ provider which actually understands Postgres and can use it to the fullest (as Revenj can).