I don't agree. For other ORMs maybe, but with SA I can get the queries coming out how I want. Also, there's not really that much magic going on – you've defined

I don't agree. For other ORMs maybe, but with SA I can get the queries coming out how I want. Also, there's not really that much magic going on – you've defined the relationships so you know how the joins will be constructed. Also, you're neglecting all the other benefits you get. Things like the loading strategies and the unit of work tracking are extremely powerful abstractions.