Strength: This is going to be twofold, because Harun's biggest strength, in my opinion, is something that will also most likely be useless to 95% of SOTF stories. Basically, after getting involved in V4's rescue, Harun had an incredibly strong Post-Game. While a lot of V4's Post-Games were extremely character-focused, and a decent number delved well into the future, Harun's pushed that really far, carrying us through Harun's career choices and well into his later years, all while keeping him recognizable as the same character we saw on the island. His development never felt cheap or forced, and the new story was markedly different from his SOTF focuses yet also fit wonderfully next to them.
In the game, Harun had a great combination of solid writing and deep relationships. While it's become more fashionable to move towards shorter posts, Harun's time on the island offers an excellent counterargument, with each of his posts actually advancing the scene and his character while also providing good detail and enough stage-setting to give a solid sense of scene. This also helped his dynamic with the other characters, particularly Rashid, with whom he spent the bulk of the game. There were a few awkward moments (particularly one where Rashid's narrative especially seemed to be dancing around implications of sexual tension between him and Harun, but in a way where it was ambiguous in a not-so-effective fashion), but by and large the two of them had good chemistry.
Weakness: While Harun didn't have it as bad as a lot of V4, his storyline in game still ran into one of the version's most common issues in that it could come across as rather insular. Harun and Rashid spend almost the whole game together, sort of falling in and out of other groups/scenes, but almost every point of impact in his story centers around the activist club or Rashid, with the rest of the island and the ongoing death game more of a backdrop than anything else. It's a good story, and Harun is nowhere near the worst offender--he actually is forced into acknowledgement of everything else at several points--but it's still fairly notable just how incidental a lot of the encounters he passes through end up in the long run. The evolution of his and Rashid's partnership is really great, but sometimes it just feels like it takes over and shoulders out other possible plot points.