The Edwardian era is getting a lot of attention now (credit Downton Abbey, perhaps?), and the details of elaborate dresses and entertainment in this ring true. There's plenty of historic detail even if replicating the language of the era sometimes falls short.
The struggles of the three girls from different backgrounds is really interesting, as is their interaction with each other. Supporting characters add some romance and depth-- interesting how Cora is mad that her employer has a new assistant, but this doesn't keep her from finding him attractive!