Genre rating (I will be giving a score of the genres in this manga for potential readers to expect, rating from "little to none (1)" to "mostly consist of (5)"):
Comedy (3) This manga is not intended to be "funny" in any sense but it has a lighthearted mood rather than a serious one.
Romance (5) This manga is solely focused on romance.
Slice of life (1) There is little to none slice of life element and no fillers besides the side stories.
Drama (2) There is very little drama in the first few chapters while only becoming prevalent towards the end.
Toshishita no Otokonoko brings nothing new or
game changing to the shoujo romance scene. It follows the generic formula of girl meets guy, feelings develop, rival-kun comes in to stir up drama, and they conclude by resolving their thoughts and emotions. However, the first 9 chapters is absolutely adorable in terms of how Mihoro and Chiel came together. It is unfortunate that the story diverts from the beginning for the sake of drama (perhaps to make Chiel realize what is most important to him).
Story (6): Toshishita no Otokonoko starts off strong with the introduction of Mihoro, who acts like a motherly figure, and her coincidental meeting with Chiel. The flags set up perfectly between the two until it reaches the climax of a so called "mood-killer confession". It is rather confusing to me why author-san would take this route as it really came out of nowhere. To put insult on this injury, author-san threw in rival-kun's arrival for the sake of completing the shoujo formula. As a result, the later chapters becomes lackluster to the adorableness until Chiel finally realizes his feelings. I would rate the beginning a solid 9 while the later chapters drop down to a 5 solely because of the poor introduction of rival-kun.
Art (8): The art style is one of the many good quirks presented in this manga. The art is neatly drawn with few inconsistencies. The facial drawings also accurately portray the character's emotions. Some of the scenic shots are also very well drawn. Although it might be similar to other shoujo mangas, author-san does not fail to deliver this consistent quality throughout the manga.
Characters (8): Unlike traditional shoujo genres, the characters in Toshishita no Otokonoko are likable and understandable from the viewers perspective. Despite the forced drama in the later chapters, it is easy to empathize with both Mihoro and Chiel: their daily activities and school but most importantly their desires and wishes. The main hero, Chiel, is not shy or perverted. He knows what he wants and he does not spend a number of chapters anguishing over his emotions. Except the part of the "mood-killer confession", one cannot find much fault in Chiel. On the other hand, Mihoro is also a likeable main heroine. Although she is shy and dense at times, we are able to see how her feelings develop to the end of the manga. Out of all the characters, she is the one who changes the most in facing her emotions by confronting rival-kun and ultimately Chiel.
To prevent myself from giving a higher score, what brought this down to an 8 is the experience of rival-kun. He ultimately did not bring much to the table in terms of shaking the feelings of Mihoro as her denseness creates a wall stronger than friendzone. We can tell the sole purpose of rival-kun is to make Chiel realize his stubbornness is only holding him back ever since the "mood-killer confession".
Enjoyment (8): To those who enjoy the formulaic shoujo genre, this is quick read that is worth your time. The fluffiness displayed between the main hero and heroine is beyond what one might expect in the early chapters of shoujo mangas. The lackluster introduction of rival-kun, however, is not much of an obstacle to the main characters. Rather I do not think it should discourage anyone who enjoys lighthearted romance presented in Toshishita no Otokonoko.