I like Monstrous Beauty. 
 ***** 
 (For the record, Wendy Darling, I still find When the Sea is Rising Red by Cat Hellisen weirder than Monstrous Beauty. Still, thank you for the reco!) 
 My second mermaid book and it was a little better than Lies Beneath (IMO). Monstrous Beauty is just that. Gory. Monstrous. Fetching. Beautiful. 
 Told in alternating POVs, between 1872/1873 (Syrenka & Ezra) and current time (Hester), and I truly enjoyed Syrenka's/Ezra's more. Their story is fuller, richer than Hester's detective skills (in history) and cold-shoulder tactics (keeping everyone she loves at a distance). 
 The mermaid tale? It was particularly terrifying and mesmerizing at the same time. Story flow was consistent; Characters were accordant to their natures. 
 My issue with it? Ghosts. Somehow, I found it misplaced with the mermaid plot. The story around mermaids was complicated enough; the paranormal element made it difficult for me to appreciate Monstrous Beauty's authenticity as a whole. 
 Monstrous Beauty is a page-turner. And I might say that I am looking forward to reading more of Fama's vengeful sea creatures. Oh yes, I am. :D