> Database schema is generated from models described in C# (or reverse-engineered from an existing schema). You don't have to compromise your schema to satisfy the ORM (another claim I often read on HN), as it's very adaptable to your needs.

Generating the schema from the models is easy mode, the ORM naturally won't generate anything it doesn't understand. The claim is that the ORM can't handle advanced schema features that it wouldn't generate. (Although in my experience most people claiming that just never bothered to learn the ORM).