I really enjoyed reading this manga, the characters are well designed and the story is interesting enough to keep you reading it. Despite being a shounen manga the plot may be a little deeper and more difficult for the younger readers to comprehend at some point.
The manga becomes more and more sad and more and more serious at the end of the story (yes, I don't like the killing off important characters in manga and anime so easily, especially character who are dear to the main character). So, I consider "the Scrapped Princess" more as a drama than an adventure comedy (although there are some funny and goofy moments in the manga).
Then, there are some moments and characters that annoy me alot (I won't tell what and who, otherwise I would spoils the story), because some characters take actions in the manga for the wrong reasons and ideas - well, there're a lot of manipulations by evil characters in the manga.
What I really like is the main character of the manga, Pacifica, the Scrapped Princess. She keeps saying she is a burden to her friends and poison to the world , while she isn't (and quite the opposite). I think she is a very brave and understanding girl, who want to help other people whenever she can. In my opinion she deserves to become the princess and eventually the queen, she has all the characteristics for being a good princess/queen. She is a much better person than her twin brother, the prince, not because he's a bad/evil character but... read the manga and you will know what I mean.
Overall, the "Scrapped Princess" is a very good and fun manga to read despite the mentioned flaws. If you like the manga, I can recommend the anime of the same title.