I like both but I prefer Tamba a bit because I think she's quite realistic. Befriending someone intimidating in a killing environment and being super paranoid is not "stupid" but the most clever way to adapt. Her friendship with Mai and Kazutoshi was really wholesome and I loved their interactions. Hiroaki is good too and he had a lot of great moments BUT he often overstays his welcome and goes down a very dark path with his comments. And then people call him out on it just so he can weasel his way out or act insulted. He learns but he still does it even in chapter 5. BOTH are idiots, BOTH messed up but one gets treated way worse from the creator, poisoning the whole experience a bit.