I personally really liked it 😀 Aki gives a new perspective to manga in a literature like way.
There were two things that surprised me: First was being that Utahime was started in media res [like in Aki's other manga Olimpos], which is really rare even in books, much less manga. It was a really unique approach that provoked my interests. In addition, Aki tackles the plot in another interesting way: she tells the ending of the story, Maria's death, early in the story. This is also not common in manga, however, it's fairly prevalent in famous classical literature such as Shakespearian plays, where the author tells the audience how the story will end in the beginning in order to help the reader understand the content of the story better. This makes me think that Aki might have had some experience in a literature major of some sort... :3
Utahime definitely doesn't seem as deep as other Aki works such as A*D or Olimpos at first, but as a reader, you really need to look deep into the details and actually think about what's going on. The hints are very subtle, so you might have to read it several times to get the actual meaning of the story. And did I mention the art is great?? A lack of details in the background as usual of Aki, but it's still great!
The only problems I'd say are the lack in background detail and Cain's personality D: [I actually liked Maria's personality more; kinda like having a dark side or imperfections with complex feelings. She's pretty much the equivalent to a femme fatal.] Cain's is a bit trite: really lucky and smart bishounen who cares for his sister very much etc etc...
But I really recommend Utahime for people who want to read something different as well as someone who wants to start reading Aki's manga [considering Utahime is the most easy to understand after Hanamatsuri].