Did you know that there exists an ersatz, modernized mashup of Frankenstein and The Count of Monte Cristo? Neither did I, until reading Schwab's Vicious.
Granted, you start a book with a character named Victor in a graveyard and you evoke certain...expectations in your reader. What impressed me about Vicious was that Schwab did not retell Frankenstein. She drew on it and paid homage to it, but the narrative has far more in common with Dumas than Shelley. (And it borrowed its pacing from the contemporary thriller, which is a relief because, well, Dumas is not known for his brevity.)
In the end, I think her willingness to tell a very strange story with all sorts of literary antecedents mixed together into a fast-paced revenge novel, rather than try to recreate a modern version of one story, made for an excellent read.