I picked this manga randomly (real meaning: I saw the review on the front page and entered. It became one of my beloved habits). This is the main result, I guess.

Story
After reading the summary for the first time, I thought about two things. First, this story has to be dark or at least very deep. Second, the plot may be slower than it's seemed to be.
I was wrong,
So wrong.
'Ai Hime' turns the forbidden love story between an uncle and a niece quickly into a light, heart-warming shojo manga. It would be even plainer, if the age different issue didn't appear. However, in some twisted way, it does the complete opposite. The main issue Mao deals with is when she will be ready to have sex with Jin; a theme that can exist perfectly with characters in the same age.
Expect form that, the manga revolves around a normal relationship under the shadow of being a family. As I mentioned before, 'Ai Hime' isn't the heavy, serious shojo it could have being. Most of the events, if not all, conclude in the same introduction of "He is my uncle" and a rapid salivation that allows Mao's and Jin's relationship grows stronger.
Even though its simplicity, I think 'Ai Hime' holds a lot of potential. In matter of fact, I believe that a longer manga would be more suitable to the storyline. Almost each chapter holds a plot that could be developed easily and leaves more impact on the reader. The short length forces the story race against time in order to touch more aspects of Mao and Jin's life.

Characters
Being the main characters of a shojo manga, Mao and Jin's personalities fit perfectly. Mao takes the rule of the cute and caring girl while Jin is the protecting yet mean, guy. The past of both of them is being told, which gives them some depth. However, the way of sharing the materials and using them, gives the feeling it didn’t reach to the peak.
Gladly enough, Mao and Jin aren't alone.
Although its short length, 'Ai Hime' has a large verity of characters. Most of them answer the average demands of their type in an alternative way. Sadly, those glimpses of depth are only given away when Jin and Mao's past involves (except from her parents who have a minor success escaping form the 'curse'). Then, after the nostalgic memories, they only serve the purpose of highlighting Jin and Mao's relationship from different aspects.
(Side note: All of the characters could have being developed much more. I am little disappointed it didn't happened. Although I hate his type of characters, I wished to see more of Satoru.)

Art
The art of 'Ai Hime' is good and more importantly it's steady through all of the manga. However, what made me impressed was the combination between two drawing style. Mao represents the shojo style while Jin has more josei characteristics in his design. Despite those differences, the art makes their coupling looks natural.
Besides that, Jin's facial expressions sometimes gave me the feeling I was looking at a different person (check out the cover of volumes 1 & 3). Other than that, form times to times, the characters' chins and lips seemed a little wired.