At the beginning I think I liked Haiji/Kakeru more but I'm not sure why, I think it's because of that one artist who draws them like in the show did top Haiji and influenced me.
Lately I prefer Kakeru topping though, especially after rewatching it. I also like the idea of Kakeru stepping up his game and taking care of Haiji, while Haiji let him see be vulnerable and handled by someone else after all this time.
I'm fine with either though. Curiously, did anyone check that fan book sequel which is even longer than the original novel?https://hasumukai.booth.pm/items/1996666#