Baker uses Pride and Prejudice as the backbone for this story of the servants at Longbourn. As far as spin-offs go, this is an interesting one. There's sadness and love and mundanity. 
 The action could have happened at any time, so the P&P reference is probably more of a selling point. People are familiar with the setting and the story, so it's easy enough for us to see what's going on above-stairs. It's a little kinder to some people (Mr. Collins, Mary) and further illustrates the perversity of others (Wickham). The foibles of the household are on full display. 
 I thought the inclusion of Ptolemy and the mentions of slavery and abolition was interesting. Bingley's wealth being build on sugar and therefore obviously slave labor. Wilberforce's writings in James' room. Wondered if this wasn't going to be a different book. 
 It's certainly interesting to see that world from less rarefied heights.