Confession time: I used to be a massive POTO fan. I've read a bunch of fic (published and not). 
 This was a fun addition to the fandom, for the most part, set in steampunk taking-over-the-world despotic-government China. It read quickly and I felt appropriately sorry for the factory ghost and admired his technical prowess (primarily with mechanics and explosions this time). 
 Secondary love interest is Melik, not an aristocrat but a minority race Noor (westerner) with red hair. I would've preferred the Noor to be a Steppes people/Mongolian, imo that would've been more believable (they can also have red hair) but whatevs. 
 What I really didn't like was keeping the entrenched patriarchal society to the extent that the heroine's only value lies in her virginity... I don't care how 'historically accurate' that might've been, it's bloody depressing, especially in a YA book. Also, (view spoiler)[did she lose it to Melik in that ice chest? That seriously should've been a more explicit yes/no given that the issue was taking up soooo much page time. (hide spoiler)] 
 I'll read the sequel, but dearly hoping that Wen grows up a bit. For all her whining about not being filial, I mean she's really not, it would've been nice for her to show a bit more gratitude to her father at the end. If you're going to keep the patriarchy, why not keep all of it? she's seriously rude to him at times, which I hated.