I'm a librarian who loves anime, manga, and reading a wide variety of genres.
This was one of those that worked for me overall but still had problems.
I enjoyed the humor, and the story was fast-paced and usually fun. I hated Alexia's habit of putting herself down and seeing herself as “less,” but it made sense in the context of what her family life was like – her mother never missed an opportunity to remind her that she wasn't society's idea of beautiful, that no one would ever want her, and that her very genetics were shameful (Alexia is half-Italian and has olive skin, which is treated as practically being a sin). The supernatural world's classification of Alexia as “soulless” probably didn't help.
I was iffy about Maccon, at first. In maturity as well as years, he seemed to be quite a bit older than Alexia. I initially thought his feelings towards her were more those of an old family friend, so when I realized he was interested in her romantically, it was a little off-putting. As the story progressed, I warmed up to him and the romantic relationship between him and Alexia that Carriger seemed to be working toward. He won loads of brownie points from me when he verbally tore into Alexia's family, while Alexia was there, for constantly putting her down and contributing to her belief that he'd never truly be interested in marrying her. He was gruff and protective, but usually not to the point of being an ass about it. His biggest problem was that he kept forgetting that Alexia wasn't a werewolf and wouldn't think to react like one, but he tried to make up for his mistakes after he was alerted to them.
Lord Akeldama was an enormous gay stereotype, but I eventually warmed up to him too. He reminded me of anime/manga characters like Break from Pandora Hearts or Fai from Tsubasa: Reservoir Chronicle – outwardly silly and fun, but secretly a badass. Alexia normally only saw the fun, silly side of Lord Akeldama, but he actually had a very extensive network of spies and was probably someone you wouldn't want to mess with.
Now for the things that didn't work for me as well. While the generally light, fun tone was nice, it didn't work with the direction the story eventually took. I couldn't take the villains or danger seriously and found myself thinking that I'd have liked the book more if Carriger had dropped the “Alexia is in danger and someone is kidnapping vampires and werewolves” parts of the story and just made it a steampunk/gaslight fantasy romance. She could have spent more time exploring the obstacles in the way of Maccon and Alexia's romance. As it was, the age, cultural, and probable lifespan differences between Maccon and Alexia were barely touched on at all.
The world-building was another area where the book faltered. There were a lot of things about Alexia's “soulless” status that I couldn't understand. Why did it have to be a secret? Not even Alexia's own family knew, so I initially assumed that all supernatural beings were also a secret...except they weren't. They even had a fairly visible place in English society. The best explanation I could think of for the secrecy surrounding soulless people was that others would want to study them to figure out how the reproduce the effect, but couldn't laws have been enacted to protect soulless people? It seemed there were laws and policies in place that governed supernaturals, so why not soulless people as well?
Aside from all of that, I wondered about soullessness in general. Alexia frequently stated that to be soulless was to be lacking something, to be “less” than others, but I saw no evidence of that. In fact, I'd argue that she was “more” - either she was a regular human who had natural protection against supernatural beings, or she was a supernatural herself, whose supernatural abilities were limited to nullifying those of other supernaturals. Who decided that soulless people were soulless? Why? The problems with the world-building bugged me.
I enjoyed this book enough that I'll probably read the next one at some point. It just may not happen for a while.
(Original review, with read-alikes, posted on A Library Girl's Familiar Diversions.)