I'm not great at writing long extended paragraphs so I'll keep it in simple bullet points!

Pros:
- Great Story: bullied high school kid learning to fight is nothing new but I found the manga's focus psychological impact of fighting quite interesting. For its themes, the manga does a great job balancing the light-hearted moments to the darker ones.
- Relatable characters: aside from one or two "big bads" the manga does a great job of showing the goods and the bads of all characters, with their inner struggles that seems realistic and relatable.
- Realistic Martial Arts: my knowledge of martial arts and fighting forms are basic but the manga seemed to show moves in an educational way, in a realistic setting (something that manga such as HSDK abandons completely)

Cons:
- Average Art: Art style is completely subjective, however it was the only weak point of the manga for me. For instance body proportion of some characters seemed completely out of place, which was especially jarring for a realistic manga about fighting. However, it did seem to improve as the chapters progressed.
- Rushed ending: while I liked the ending I feel like it could have benefited greatly from 3~5 extra chapters, something that many manga suffer from unfortunately.

Overall: Focus on character is what makes most psychological mangas great as a genre and 'Holyland' managed also do so whilst avoiding the pitfalls of the genre by having the plot be entirely tragic and depressing. I read it reluctantly at my friends recommendation and ended up re-reading it around 3 times in the last few years. Highly recommended for all who wants to take a break from the trope-filled shounen battle manga.