My rating always reflects whether or not I enjoy a story -- it can be influenced by a lot of factors, not necessarily the quality of the story. And I have problems with this book...
*) I dislike reading accent immensely ... especially Irish/Scottish accent or what I like to call as British tone. I am an ESL, I already reading in a language that is not my own. Call me a lazy reader but reading books with accent is extra work for me to understand the conversation. It's one of the major reasons why I avoid historical romance (though lately I find that I can enjoy MM historical romance). This one has it and I struggled. Boy did I struggle. I ended up skimming.
*) The book is marketed as Gaslight Mysteries. Unfortunately I felt that the mystery part was overshadowed by the sexual part. Yeah, too much sex for a mystery book. I don't mind romance in my mystery, but not so much the sex. For me, the two are NOT mutually inclusive.
*) Talk about the sex ... quite a few of dubious consents situation for my liking. I never like yaoi trope in my romance ... the "Your mouth says no but your body says yes" thing? It's too close to rape in my mind. I can read yaoi/dub-con/non-con but I prefer to know what I'm getting into. So for me Michael was being too pushy, and border to harassment when he approached Simon, whom Michael admitted himself was still mourning over the death of his friend.
All in all, I didn't enjoy the writing, the characters, or the mystery. Thus my low rating :(